This June there will be a Meeting-in-a-Meeting during the 242nd gathering of the American Astronomical Society (AAS) in Albuquerque, NM entitled, "Standing on the Wings of SOFIA.” This event will be a forum to discuss key results from SOFIA’s decade-long mission, with topics ranging from the Solar System to distant galaxies, and will explore how the SOFIA legacy can provide a foundation for the FIR Probe concepts currently under development in response to the recommendations by the 2020 Decadal Survey.
This event will consist of five 90-min sessions over three days and will cover four general topics where SOFIA has had a significant impact to the development of infrared astronomy: ISM/Star formation, Magnetic Fields/Dust physics, Galaxy Structure, and Stars/Solar system. The last day will be dedicated to discussion of future far-IR instrumentation and missions, especially the four FIR Probes.
Please note: on the current AAS schedule, the "Standing on the Wings of SOFIA" Meeting-in-a-Meeting is listed by each individual session and not by its main title. Individual session titles are:
- Galactic Ecosystems: ISM & Star Formation
- Galactic Ecosystems: Magnetic Fields and Dust Physics
- Galactic Ecosystems: Galaxy Structure and Evolution
- New Worlds/Time Domain: Stars and Solar System
- The Future of FIR Astronomy
Schedule and Speakers
All times are Mountain Time
Monday, June 5
Albuquerque Convention Center, Meeting Room 215
10:00 AM – 11:30 AM
108: Galactic Ecosystems: ISM & Star Formation
10:00-10:20 AM
108.01 S. Thomas Megeath (University of Toledo): Wings of Far-IR: Exploring accretion and outflow towards low to Intermediate mass protostars with SOFIA
Abstract: With its ability to observe at mid to far-IR wavelength, SOFIA was an essential complement to NASA and ESA’s space observatories. We overview SOFIA’s contributions to studies of low to intermediate mass star formation, focusing on two areas of discovery. We first show how HAWC+ and FORCAST, when compared to Spitzer and Herschel data, measured the changing luminosities of young stars and protostars undergoing bursts of rapid mass accretion. These data show the evolution of outbursts and constrain the fraction of a star’s mass accreted during bursts. We then move to outflows. Here we show how the high spectral resolution of the GREAT/upGREAT instruments, when combined with the high angular resolution of HST and JWST, can be used to measure the motions and properties of jets launched by intermediate mass protostars. Finally, we briefly discuss the potential of the SOFIA archive for future studies in star formation.
10:20-10:35 AM
108.02 Matthew Hankins (Arkansas Tech University): SOFIA's View of Massive Stars and Star Forming Regions
Abstract: Understanding the formation and evolution of massive stars is an important area of study in astronomy. Massive stars have a tremendous impact on their natal environments via feedback processes and similarly influence future generations of forming stars. While there are several theories related to the formation of massive stars, there are still many open questions that are active areas of research. Given that massive stars are relatively rare compared to low-mass counterparts, further study and characterization of high mass protostars can provide important clues to aid in our understanding of the star formation process. Over the past decade, The Stratospheric Observatory for Infrared Astronomy (SOFIA) has played a key role in studies of high mass star formation, with instrumentation at mid- to far-IR wavelengths that can probe the earliest phases of star formation and also study massive star forming complexes. In this talk, I will present an overview and reflection on SOFIA results related to massive star formation and massive star forming regions from a variety of programs carried out by the observatory.
10:35-11:00 AM
108.03 Arshia Jacob (John Hopkins University): Fingerprinting the chemical Universe: A tale of GREAT hydride observations
Abstract: Owing to the complexity of their energy level structures and as a result their chemical fingerprints or spectra– molecules, observed in either emission or absorption form unique diagnostic probes of the physical conditions in which they are found. In addition to forming excellent probes of astronomical conditions, molecules play a central role in influencing the thermal and ionization structure of gas, initiating condensations and instabilities responsible for the formation of stars and as a result regulate the evolution of the environments in which they are formed. While astronomical spectra reveal a wealth of knowledge, their interpretation is complicated by the need for a detailed understanding of their chemistry and often limited to the study of simpler systems such as light hydrides (molecules/molecular ions with a heavy atom covalently bonded to one or more hydrogen atoms). In this talk, I will highlight the use of hydrides in addressing one of the fundamental questions in modern astronomy that concerns the life cycle of molecular material in the universe. I will emphasis HyGAL, a SOFIA-GREAT Legacy program aimed to address several questions related to the HI-to-H2 phase transition (responsible for molecular cloud formation) and star-formation in general using observations of hydrides, such as (1) What is the distribution of the H2 fraction in the ISM? (2) How does the density of low-energy cosmic-rays vary within in the Galaxy and (3) What is the nature of interstellar turbulence and what mechanisms lead to dissipation? I will conclude by discussing the valuable legacy provided by HyGAL for future studies of the ISM and the role it plays in future hydride observations.
11:00-11:15 AM
108.04 Ümit Kavak (SOFIA Science Center/USRA/NASA): SOFIA FEEDBACK Survey: Interplay between protostellar and main-sequence feedback mechanisms in NGC 7538
Abstract: Radiative and mechanical feedback from massive stars rigorously controls star formation and galaxy evolution. Modern astronomy has one of its greatest challenges in attempting to characterize the stellar feedback modes in various massive star-forming regions of the Galaxy. Recent SOFIA [CII] observations at 158 microns from the SOFIA C+ SQUAD Large Program estimated the relative importance of feedback mechanisms provided by protostellar and main-sequence phases in the Orion Veil shell. Namely, Pabst et al. (2022) and Kavak et al. (2022) determined that protostellar feedback is one-sixth of the feedback provided during the main sequence phase of the Trapezium cluster, which contains an O6-type star in the Orion Nebula. We focus on another massive star-forming region to see if there is a correlation between protostellar and main-sequence feedback mechanisms. We will present the results obtained from NGC 7538, which is one of the essential SOFIA FEEDBACK Legacy Program sources. Two O-type stars (IRS-5 and IRS-6) in NGC 7538 are responsible for the expansion of the HII region, which interacts with a powerful outflow from IRS-1, an O-type star, in the formation process. In addition, NGC 7538 is considerably more evolved than the Orion Nebula. Moreover, the measured size of the HII region is almost two times bigger than the theoretical Strömgen sphere. In this talk, we will discuss the main driving mechanisms in NGC 7538 and compare them with the results of the Orion Nebula.
11:15-11:30 AM
108.05 Edward Montiel (SOFIA/USRA): An Overview of the EXES/SOFIA Archive
Abstract: The Echelon-Cross-Echelle Spectrograph (EXES) was a mid-IR (5 -- 28 μm) spectrograph that flew on SOFIA from 2015 to 2022. This wavelength regime is home to ro-vibrational transitions, non-polar molecules, and some common forbidden emission lines. A diverse number of astronomical sources, ranging from Solar System objects to external galaxies, were observed with spectral resolutions ranging from R of about 2,000 up to 100,000 over its 78 number of flights. These observations are capable of providing a comprehensive understanding of abundances, chemistry, and kinematics of sources than similar observations at lower resolution. We will highlight cohesive, publicly available EXES datasets, especially those that have links to accepted JWST programs.
2:00 PM – 3:30 PM
117: Galactic Ecosystems: Magnetic Fields and Dust Physics
2:00-2:25 PM
117.01 Thushara Pillai (MIT Haystack Observatory): SOFIA view of Magnetic Fields in the Cold Interstellar Medium
Abstract: Molecular clouds in the interstellar medium that are forming stars are magnetized. The magnetic fields of these clouds may be inherited from the larger galactic interstellar medium. The orientation of filamentary clouds appears to be influenced by these magnetic fields. The relative orientation of magnetic fields, filaments, and dense clumps within them provides information about the relative importance of forces due to magnetic fields and gravity. Using SOFIA’s HAWC+ instrument, it was possible to capture the magnetic field structure of the larger interstellar medium of molecular clouds, ranging from several tens of parsecs to dense star-forming cores of less than 0.1 pc, at high spatial resolution. In this presentation, I will provide an overview of SOFIA’s unique perspective on the role of magnetic fields in the formation of molecular clouds in various environments from the Gould Belt to distant spiral arms, as well as their effect on star formation.
2:25-2:50 PM
117.02 Charles D. Dowell (Jet Propulsion Laboratory): Extragalactic Magnetic Fields Mapped in the Far Infrared with HAWC+ on SOFIA
Abstract: An important legacy from HAWC+ polarimetry on SOFIA is the demonstration that magnetic fields can be detected and analyzed in star-forming galaxies in the far infrared. Fifteen galaxies, and also the 30 Doradus region of the Large Magellanic Cloud, were mapped in polarization within the 53 to 214 micron wavelength range, where the emission traces primarily dense gas heated by young stars, providing unique insights to the magnetic fields in these galaxies. All of the galaxies studied have detectable polarization fraction in the range 1% to 3% or more. The more face-on spiral galaxies in the sample (M51, NGC 1068, and others) show a clear ordered spiral component on scales of several kpc. The edge-on spirals show a mix of planar and, in a minority of cases, outflow field structures, with outflows more visible in the warmer dust emission. The most edge-on galaxy, NGC 891, shows only an isolated instance of outflow magnetic field (perpendicular to the plane) and otherwise a surprisingly low fractional polarization outside the plane, suggesting disordered magnetic fields there. The magnetic field maps of the spirals also trace bar and other nuclear features in the galaxies. In the category of merger systems, the magnetic field in the warped disk of Centaurus A has been studied in detail, and polarization has been mapped in the Antennae galaxy pair including the tidal tail. The successful effort with HAWC+ sets the stage for further breakthroughs in extragalactic magnetic field studies with a cryogenic space telescope.
2:50-3:10 PM
117.03 B-G Andersson (SOFIA Science Center/USRA): Understanding Interstellar Polarimetry -- Grain Alignment and Physical Scales
Abstract: Dust induced polarization, from the UV to mm-waves, is an efficient way to probe the magnetic fields in the interstellar medium (ISM), but relies on a quantitative understanding of the underlying grain alignment, along the line of sight. With the development of the paradigm of Radiative Alignment Torque (RAT) theory, major advances have been made in understanding how and where the polarization is generated. However, several details of the alignment physics still need to be fully understand, as well as the effect of the environment on different scales. We will discuss some of the open questions in grain alignment as well as highlight how different physical scales and the polarization spectrum (with an emphasis on the FIR/sub-mm wave) can be used to further improve our understanding of the ISM magnetic fields, as well as the roles of grain characteristics and environmental parameters affect their measurements.
3:10-3:30 PM
117.04 Margaret Meixner (Jet Propulsion Laboratory, California Institute of Technology): Building on SOFIA's Legacy, open questions in Galactic Ecosystems
Abstract: The interstellar medium (ISM) emits a tremendous amount of radiation in the infrared (3 to 500 microns) that represents the majority of the light emitted by a galaxy. The Stratospheric Observatory For Infrared Astronomy (SOFIA) covered this entire wavelength range with 5 instruments including spectrometers, imagers and polarimeters. The Astro2020 Decadal survey recognizes the importance of the far-infrared (far-IR) recommending future missions. In this talk I will review highlights of SOFIA’s legacy in Galactic Ecosystems which includes ISM, and star formation. Moreover, I will outline the many remaining open questions left for future missions and how they relate to the decadal survey’s questions.
Tuesday, June 6
Albuquerque Convention Center, Meeting Room 215
10:00 AM – 11:30 AM MDT
210: Galactic Ecosystems: Galaxy Structure and Evolution
10:00-10:25 AM
210.01 Andrew Harris (University of Maryland, College Park): Understanding our Galactic center with SOFIA
Abstract: This talk reviews some of the most important advances SOFIA has made to our understanding of our Galactic center. Instruments on SOFIA probed the mid- and far-infrared in continuum, spectral lines, and polarization, tracing energy deposition, physical conditions, and magnetic fields across the region. These have provided a vastly improved view of the 200 pc-wide Circum-Nuclear Zone (CMZ) containing material that orbits the nuclear core, and also of material close to the Galaxy's 4 million solar mass black hole. SOFIA observations have provided information crucial to understanding key interactions within this complex region. Deep at the bottom of the Galaxy's potential well, the Galactic center is home to extremes in stellar density, stellar properties, and energy density. Collisions and orbital shear regulate star formation in massive molecular clouds like nowhere else in the Galaxy. SOFIA studies tell us not only about processes and structures in our own Galaxy, but provide a level of detail unachievable in any other galaxy to help us understand galactic nuclei everywhere in the universe.
10:25-10:45 AM
210.02 Dario Fadda (SOFIA/USRA): The [CII] 158µm line emission in nearby Galaxies
Abstract: The 158.7um emission line from the singly ionized carbon is the brightest far-IR line emitted by galaxies, usually amounting to 1% or more of the total far-IR continuum. Since the line acts as the main cooling channel for photodissociation regions in the interstellar medium (ISM), it is essential to study the properties of the ISM in high redshift galaxies, as recently shown by ALMA observations. However, because of the low ionization potential of carbon, C+ exists in a variety of environments, from HII regions to warm molecular clouds. Moreover, mechanisms different than stellar emission can significantly contribute to the emission. It is therefore essential to study in detail the contribution of the different ISM regions and mechanism of emission of C+ in nearby galaxies to better infer the properties of the ISM in distant galaxies. We will show how Herschel and SOFIA observations of nearby extended galaxies have shed new light on the C+ emission origin and its relationship with star formation rates in galaxies.
10:45-11:00 AM
210.03 Christopher Hayward (Flatiron Institute): The effect of AGN on host-galaxy dust heating
Abstract: Theorists have recently started to examine the effects of AGN radiation on dust heating on host galaxy scales via performing dust radiative transfer on simulated AGN-hosting galaxies. We and others have found that in some cases, obscured AGN heating can dominate the galaxy-scale cold dust emission, even at rest-frame wavelengths >100 micron. I will summarize these results and discuss implications for using FIR emission as a star formation rate tracer.
11:00-11:10 AM
210.04 Randolf Klein (SOFIA/USRA): The Photodissociation and Ionization Fronts in M17-SW Localized with FIFI-LS on Board SOFIA
Abstract: To understand star formation rates, studying feedback mechanisms that regulate star formation is necessary. The radiation emitted by nascent massive stars play a significant role in feedback by photodissociating and ionizing their parental molecular clouds. To gain a detailed picture of the physical processes, we mapped the photodissociation region (PDR) M17-SW in several fine-structure and high-J CO lines with FIFI-LS, the far- infrared imaging spectrometer aboard SOFIA. An analysis of the CO and [O I]146 μm line intensities, combined with the far-infrared intensity, allows us to create a density and UV intensity map using a one-dimensional model. The density map reveals a sudden change in the gas density crossing the PDR. The strengths and limits of the model and the locations of the ionization and photodissociation front of the edge-on PDR are discussed.
11:10-11:20 AM
Ka Wai Ho (UW-Madison): The "stable" thermal unstable medium and its effect on cold filament in multi-phase ISM
Abstract: The ubiquity of very thin and lengthy cold neutral medium (CNM) has been reported by multiple authors in the H I community. Yet, the reason of how the CNM can be so long and lengthy is still in debate. In this paper, we recognize a new type of instability due to the attractive nature of the pressure force in the unstable phase. Furthermore, we demonstrate that the presence of turbulence can stabilize the originally unstable phase through its mixing effects. We provide a new estimation of the average CNM filament aspect ratio with the consideration of force balances at the phase boundary, which is roughly 5–20 in common CNM environment. We show that most of the cold filaments are less filamentary than what usually predicted via MHD turbulence theory or inferred from observations: The average length of CNM filament is roughly 1/2 of that in isothermal MHD turbulence with similar turbulence conditions. This suggests that the ‘cold filaments’ that are identified in observations might not be in pressure equilibrium or generated via other mechanisms.
2:00 PM – 3:30 PM MDT
223: New Worlds/Time Domain: Stars and Solar System
2:00-2:25 PM
223.01 Kathleen Kraemer (Boston College): Stellar Evolution through the Lens of SOFIA -- Highlights of Evolved Star Investigations
Abstract: Over the last decade, the astronomical community used the Stratospheric Observatory for Infrared Astronomy (SOFIA) to investigate nearly every phase of stellar evolution. Evolved stars, which have left the main sequence, were particularly well suited for study with the suite of instruments on SOFIA. Targets of such studies included asymptotic giant branch (AGB) stars, red supergiants, Wolf-Rayet stars, luminous blue variables, novae, post-AGB stars, planetary nebulae, and supernova remnants. These objects are actively shedding or have recently shed the bulk of their mass, and this newly enriched material will be recycled into the next generations of stars and planets. The grains and molecules that are forming in and around these evolved sources have a plethora of signatures in the infrared with which to trace the physical and chemical conditions of the gas and dust and that of the stars which produced them. This talk reviews some of the discoveries and new insights that came from observations with EXES, FIFI-LS, FLITECAM, FORCAST, GREAT, and HAWC+, advancing our understanding of evolved stars and stellar evolution. Many thanks to the SOFIA instrument teams, flight crews, and staff scientists for making these studies possible, including building the instruments, making the observations, and creating high-quality data products, and to the science teams whose work is reviewed here. SOFIA was jointly operated by the Universities Space Research Association, Inc. (USRA), under NASA contract NNA17BF53C, and the Deutsches SOFIA Institut (DSI) under DLR contract 50 OK 0901 to the University of Stuttgart.
2:25-2:45 PM
223.02 Robert Gehrz (University of Minnesota): Infrared Observations of Novae with SOFIA and Beyond
Abstract: Thermonuclear runaways (TNRs) on the surfaces of white dwarf (WD) stars accreting matter in close binary systems produce classical nova explosions that may play an important part in producing some of the isotopic anomalies that are present in the remnants of the primitive solar system. We review the use of infrared (IR) photometric and spectroscopic observations to quantify the physical parameters of classical nova outbursts and to assess their contributions to the interstellar medium (ISM) where star formation occurs. Metal abundances in the ejecta can be deduced from dust emission features and metallic forbidden line emission. The observations described here also provide basic information about the TNR that causes the nova explosion, the chemical composition of the WD upon which the TNR occurs, and the nature of the WD's progenitor star. We show that some recent bright novae have ejected shells that are extremely overabundant in C, N, O, Ne, Mg, Al, and Si. The properties of dust grains produced by novae are reviewed and compared to those of the dust grains observed in preplanetary nebulae and dust grains released from comet nuclei. By analogy to novae, supernovae (both Types I and II) and stellar mergers produce ejecta that enrich the ISM and contribute the building blocks of life and planets to new stellar and planetary systems. We review observations of novae made with the Spitzer Space Telescope and the NASA Stratospheric Observatory for Infrared Astronomy (SOFIA). We anticipate the impact that these observations will have on the definition of proposed FIR Probe missions, such as the PRobe far-Infrared Mission for Astrophysics (PRIMA), that will observe novae, stellar mergers, and supernova explosions.
2:45-3:10 PM
233.03 Dariusz Lis (Jet Propulsion Laboratory, California Institute of Technology): SOFIA Solar System Legacy
Abstract: I will present highlights of SOFIA studies of Solar System objects, including observations of water in the lunar south pole region, measurements of the D/H ratio in water in the atmosphere of Mars and in comets, as well as occultations of Pluto.
3:10-3:30 PM
223.04 Laura Lenkić (USRA): Building on SOFIA's Legacy: Future Prospects for Extragalactic Astronomy
Abstract: More than half of the energy output of galaxies is in the form of mid- to far-infrared radiation at 5-500 μm; consequently, the infrared is a tool of significant importance in our pursuit of understanding star formation and galaxy evolution. The Astro2020 Decadal Survey recognizes the importance of the infrared, as nearly half of the questions raised by the Decadal can be studied with the tools of infrared astronomy. In this talk, I will first review some of the scientific highlights of the Stratospheric Observatory for Infrared Astronomy (SOFIA) mission in the field of extragalactic astronomy, such as (among others) 1) how observations of local analogs to high-redshift galaxies enable studies of the dust, star formation, and star formation history properties of these systems, 2) how observations of high-redshift galaxies can help constrain the AGN and star forming contributions to far-infrared luminosity, and 3) how polarization observations at far-infrared wavelengths can reveal the geometry of the magnetic fields of galaxies and star forming regions, and help us understand how galaxies exchange metal enriched gas with their surrounding environment and the role of magnetic fields in star formation at the sub-parsec scale. Following this review, I will discuss how these SOFIA results pave the path for future important research areas in far-infrared extragalactic astronomy, including synergies with multi-messenger and time domain astronomy.
Wednesday, June 7
Albuquerque Convention Center, Meeting Room 215
10:00 AM – 11:30 AM MDT - 44
314: The Future of FIR Astronomy
10:00-10:20 AM
314.01 Michael Zemcov (Rochester Institute of Technology): Cold, Small, and Plentiful: the Future of Instrumentation for Far-IR Astrophysics
Abstract: Observations at far-infrared (FIR) wavelengths are critical to advancing our understanding in nearly all areas of astrophysics, from the search for habitable planets and the origin of life all the way back to the earliest stages of galaxy assembly. A developing portfolio of technologies, particularly in the field of spectrographic imaging, hold the promise of paradigm-shifting advances in scientific understanding. In this talk, I review the landscape of techologies of strategic importance to meeting the science goals in recent State-of-the-Field reports, examine the advancement of existing and new observing platforms, and discuss possible paths to best address the challenges facing far-infrared astronomy in this decade and beyond.
10:20-10:32 AM
314.02 Jason Glenn (NASA GSFC): PRIMA: the PRobe far-Infrared Mission for Astrophysics
Abstract: PRIMA is a far-infrared observatory concept being developed to address timely and fundamental questions about the growths of galaxies and solar systems and their constituents. It will observe the build-up of stars, black holes, and dust in galaxies over cosmic time, and trace the masses and water contents of protoplanetary disks to probe the growths of solar systems. The majority of observing time will be devoted to Guest Observer programs, with focused PI programs to address key science to inform community planning. PRIMA will have spectral, hyperspectral imaging, and polarimetric capabilities, enabled now for the first time by extraordinary progress in kinetic inductance detector (KID) array technology over the last two decades. The telescope will be cooled to 5 K to take maximum advantage of the KID sensitivities. For observations of atomic fine-structure lines, molecular lines, and solid-state emission and absorption bands, R = 130 spectral coverage will range from approximately 24 microns to 240 microns, with a high-resolution mode across the entire band that will have a spectral resolving power of a few thousand at 100 microns. R ~ 10 moderate-resolution (hyperspectral) imaging will range from 25 to 80 microns for rest-frame, mid- and far-infrared spectral energy distribution measurements to disambiguate star formation and active galactic nuclei in galaxies and to probe dust grain composition. Polarimetric observations from 80 to ~200 microns will bridge between the large-scale polarimetry of the interstellar medium from cosmic microwave background observatories and protostellar disk-scale interferometric observations to probe magnetic fields at the critical scales at which clouds collapse to form stars. An overview of PRIMA’s basic design and capabilities will be presented.
10:32-10:44 AM
Christopher Walker (University of Arizona): Single Aperture Large Telescope for Universe Studies (SALTUS)
Abstract: SALTUS (Single Aperture Large Telescope for Universe Studies) is a Probe mission concept that employs a radiatively cooled, 20 meter inflatable aperture and cryogenic detectors to better understand our cosmic origins and the possibility of life elsewhere. The science objectives of SALTUS are to: 1) Trace astrochemical signatures of planet formation, habitable zones, and life. 2) Trace galaxy evolution and heavy element production over cosmic time. 3) Perform a census and probe the structure of supermassive black holes. To achieve these objectives SALTUS will perform spectroscopic studies towards 100’s of exoplanets, protoplanetary disks, galaxies, and solar system objects over a wavelength range from ~30 to 300 microns at high and moderate spectral resolution. The focal plane will include both coherent and incoherent detectors cooled by a closed-cycle refrigeration system. The telescope will employ a sunshield and be radiatively cooled to ~45K. SALTUS will have ~10x the collecting area of JWST and ~30x that of Herschel. The 20 meter aperture of SALTUS will be used as a space node for millimeter-wave VLBI observations of massive black holes in the Milky Way and beyond. The mission is designed to provide a lifetime of > 5 years. More than 50% of its on-orbit time will be dedicated to the SALTUS Guest Observer (GO) Program. With its large aperture and suite of instruments, SALTUS will provide a quantum leap in our understanding of the universe.
10:44-10:56 AM
314.04 Asantha Cooray (University of California, Irvine): TBD
10:56-11:30 AM
Panel Discussion led by Erick Young (USRA)
This June there will be a Meeting-in-a-Meeting during the 242nd gathering of the American Astronomical Society (AAS) in Albuquerque, NM entitled, "Standing on the Wings of SOFIA.” This event will be a forum to discuss key results from SOFIA’s decade-long mission, with topics ranging from the Solar System to distant galaxies, and will explore how the SOFIA legacy can provide a foundation for the FIR Probe concepts currently under development in response to the recommendations by the 2020 Decadal Survey.
This event will consist of five 90-min sessions over three days and will cover four general topics where SOFIA has had a significant impact to the development of infrared astronomy: ISM/Star formation, Magnetic Fields/Dust physics, Galaxy Structure, and Stars/Solar system. The last day will be dedicated to discussion of future far-IR instrumentation and missions, especially the four FIR Probes.
Please note: on the current AAS schedule, the "Standing on the Wings of SOFIA" Meeting-in-a-Meeting is listed by each individual session and not by its main title. Individual session titles are:
- Galactic Ecosystems: ISM & Star Formation
- Galactic Ecosystems: Magnetic Fields and Dust Physics
- Galactic Ecosystems: Galaxy Structure and Evolution
- New Worlds/Time Domain: Stars and Solar System
- The Future of FIR Astronomy
Schedule and Speakers
All times are Mountain Time
Monday, June 5
Albuquerque Convention Center, Meeting Room 215
10:00 AM – 11:30 AM
108: Galactic Ecosystems: ISM & Star Formation
10:00-10:20 AM
108.01 S. Thomas Megeath (University of Toledo): Wings of Far-IR: Exploring accretion and outflow towards low to Intermediate mass protostars with SOFIA
Abstract: With its ability to observe at mid to far-IR wavelength, SOFIA was an essential complement to NASA and ESA’s space observatories. We overview SOFIA’s contributions to studies of low to intermediate mass star formation, focusing on two areas of discovery. We first show how HAWC+ and FORCAST, when compared to Spitzer and Herschel data, measured the changing luminosities of young stars and protostars undergoing bursts of rapid mass accretion. These data show the evolution of outbursts and constrain the fraction of a star’s mass accreted during bursts. We then move to outflows. Here we show how the high spectral resolution of the GREAT/upGREAT instruments, when combined with the high angular resolution of HST and JWST, can be used to measure the motions and properties of jets launched by intermediate mass protostars. Finally, we briefly discuss the potential of the SOFIA archive for future studies in star formation.
10:20-10:35 AM
108.02 Matthew Hankins (Arkansas Tech University): SOFIA's View of Massive Stars and Star Forming Regions
Abstract: Understanding the formation and evolution of massive stars is an important area of study in astronomy. Massive stars have a tremendous impact on their natal environments via feedback processes and similarly influence future generations of forming stars. While there are several theories related to the formation of massive stars, there are still many open questions that are active areas of research. Given that massive stars are relatively rare compared to low-mass counterparts, further study and characterization of high mass protostars can provide important clues to aid in our understanding of the star formation process. Over the past decade, The Stratospheric Observatory for Infrared Astronomy (SOFIA) has played a key role in studies of high mass star formation, with instrumentation at mid- to far-IR wavelengths that can probe the earliest phases of star formation and also study massive star forming complexes. In this talk, I will present an overview and reflection on SOFIA results related to massive star formation and massive star forming regions from a variety of programs carried out by the observatory.
10:35-11:00 AM
108.03 Arshia Jacob (John Hopkins University): Fingerprinting the chemical Universe: A tale of GREAT hydride observations
Abstract: Owing to the complexity of their energy level structures and as a result their chemical fingerprints or spectra– molecules, observed in either emission or absorption form unique diagnostic probes of the physical conditions in which they are found. In addition to forming excellent probes of astronomical conditions, molecules play a central role in influencing the thermal and ionization structure of gas, initiating condensations and instabilities responsible for the formation of stars and as a result regulate the evolution of the environments in which they are formed. While astronomical spectra reveal a wealth of knowledge, their interpretation is complicated by the need for a detailed understanding of their chemistry and often limited to the study of simpler systems such as light hydrides (molecules/molecular ions with a heavy atom covalently bonded to one or more hydrogen atoms). In this talk, I will highlight the use of hydrides in addressing one of the fundamental questions in modern astronomy that concerns the life cycle of molecular material in the universe. I will emphasis HyGAL, a SOFIA-GREAT Legacy program aimed to address several questions related to the HI-to-H
2
phase transition (responsible for molecular cloud formation) and star-formation in general using observations of hydrides, such as (1) What is the distribution of the H
2
fraction in the ISM? (2) How does the density of low-energy cosmic-rays vary within in the Galaxy and (3) What is the nature of interstellar turbulence and what mechanisms lead to dissipation? I will conclude by discussing the valuable legacy provided by HyGAL for future studies of the ISM and the role it plays in future hydride observations.
11:00-11:15 AM
108.04 Ümit Kavak (SOFIA Science Center/USRA/NASA): SOFIA FEEDBACK Survey: Interplay between protostellar and main-sequence feedback mechanisms in NGC 7538
Abstract: Radiative and mechanical feedback from massive stars rigorously controls star formation and galaxy evolution. Modern astronomy has one of its greatest challenges in attempting to characterize the stellar feedback modes in various massive star-forming regions of the Galaxy. Recent SOFIA [CII] observations at 158 microns from the SOFIA C+ SQUAD Large Program estimated the relative importance of feedback mechanisms provided by protostellar and main-sequence phases in the Orion Veil shell. Namely, Pabst et al. (2022) and Kavak et al. (2022) determined that protostellar feedback is one-sixth of the feedback provided during the main sequence phase of the Trapezium cluster, which contains an O6-type star in the Orion Nebula. We focus on another massive star-forming region to see if there is a correlation between protostellar and main-sequence feedback mechanisms. We will present the results obtained from NGC 7538, which is one of the essential SOFIA FEEDBACK Legacy Program sources. Two O-type stars (IRS-5 and IRS-6) in NGC 7538 are responsible for the expansion of the HII region, which interacts with a powerful outflow from IRS-1, an O-type star, in the formation process. In addition, NGC 7538 is considerably more evolved than the Orion Nebula. Moreover, the measured size of the HII region is almost two times bigger than the theoretical Strömgen sphere. In this talk, we will discuss the main driving mechanisms in NGC 7538 and compare them with the results of the Orion Nebula.
11:15-11:30 AM
108.05 Edward Montiel (SOFIA/USRA): An Overview of the EXES/SOFIA Archive
Abstract: The Echelon-Cross-Echelle Spectrograph (EXES) was a mid-IR (5 -- 28 μm) spectrograph that flew on SOFIA from 2015 to 2022. This wavelength regime is home to ro-vibrational transitions, non-polar molecules, and some common forbidden emission lines. A diverse number of astronomical sources, ranging from Solar System objects to external galaxies, were observed with spectral resolutions ranging from R of about 2,000 up to 100,000 over its 78 number of flights. These observations are capable of providing a comprehensive understanding of abundances, chemistry, and kinematics of sources than similar observations at lower resolution. We will highlight cohesive, publicly available EXES datasets, especially those that have links to accepted JWST programs.
2:00 PM – 3:30 PM
117: Galactic Ecosystems: Magnetic Fields and Dust Physics
2:00-2:25 PM
117.01 Thushara Pillai (MIT Haystack Observatory): SOFIA view of Magnetic Fields in the Cold Interstellar Medium
Abstract: Molecular clouds in the interstellar medium that are forming stars are magnetized. The magnetic fields of these clouds may be inherited from the larger galactic interstellar medium. The orientation of filamentary clouds appears to be influenced by these magnetic fields. The relative orientation of magnetic fields, filaments, and dense clumps within them provides information about the relative importance of forces due to magnetic fields and gravity. Using SOFIA’s HAWC+ instrument, it was possible to capture the magnetic field structure of the larger interstellar medium of molecular clouds, ranging from several tens of parsecs to dense star-forming cores of less than 0.1 pc, at high spatial resolution. In this presentation, I will provide an overview of SOFIA’s unique perspective on the role of magnetic fields in the formation of molecular clouds in various environments from the Gould Belt to distant spiral arms, as well as their effect on star formation.
2:25-2:50 PM
117.02 Charles D. Dowell (Jet Propulsion Laboratory): Extragalactic Magnetic Fields Mapped in the Far Infrared with HAWC+ on SOFIA
Abstract: An important legacy from HAWC+ polarimetry on SOFIA is the demonstration that magnetic fields can be detected and analyzed in star-forming galaxies in the far infrared. Fifteen galaxies, and also the 30 Doradus region of the Large Magellanic Cloud, were mapped in polarization within the 53 to 214 micron wavelength range, where the emission traces primarily dense gas heated by young stars, providing unique insights to the magnetic fields in these galaxies. All of the galaxies studied have detectable polarization fraction in the range 1% to 3% or more. The more face-on spiral galaxies in the sample (M51, NGC 1068, and others) show a clear ordered spiral component on scales of several kpc. The edge-on spirals show a mix of planar and, in a minority of cases, outflow field structures, with outflows more visible in the warmer dust emission. The most edge-on galaxy, NGC 891, shows only an isolated instance of outflow magnetic field (perpendicular to the plane) and otherwise a surprisingly low fractional polarization outside the plane, suggesting disordered magnetic fields there. The magnetic field maps of the spirals also trace bar and other nuclear features in the galaxies. In the category of merger systems, the magnetic field in the warped disk of Centaurus A has been studied in detail, and polarization has been mapped in the Antennae galaxy pair including the tidal tail. The successful effort with HAWC+ sets the stage for further breakthroughs in extragalactic magnetic field studies with a cryogenic space telescope.
2:50-3:10 PM
117.03 B-G Andersson (SOFIA Science Center/USRA): Understanding Interstellar Polarimetry -- Grain Alignment and Physical Scales
Abstract: Dust induced polarization, from the UV to mm-waves, is an efficient way to probe the magnetic fields in the interstellar medium (ISM), but relies on a quantitative understanding of the underlying grain alignment, along the line of sight. With the development of the paradigm of Radiative Alignment Torque (RAT) theory, major advances have been made in understanding how and where the polarization is generated. However, several details of the alignment physics still need to be fully understand, as well as the effect of the environment on different scales. We will discuss some of the open questions in grain alignment as well as highlight how different physical scales and the polarization spectrum (with an emphasis on the FIR/sub-mm wave) can be used to further improve our understanding of the ISM magnetic fields, as well as the roles of grain characteristics and environmental parameters affect their measurements.
3:10-3:30 PM
117.04 Margaret Meixner (Jet Propulsion Laboratory, California Institute of Technology): Building on SOFIA's Legacy, open questions in Galactic Ecosystems
Abstract: The interstellar medium (ISM) emits a tremendous amount of radiation in the infrared (3 to 500 microns) that represents the majority of the light emitted by a galaxy. The Stratospheric Observatory For Infrared Astronomy (SOFIA) covered this entire wavelength range with 5 instruments including spectrometers, imagers and polarimeters. The Astro2020 Decadal survey recognizes the importance of the far-infrared (far-IR) recommending future missions. In this talk I will review highlights of SOFIA’s legacy in Galactic Ecosystems which includes ISM, and star formation. Moreover, I will outline the many remaining open questions left for future missions and how they relate to the decadal survey’s questions.
Tuesday, June 6
Albuquerque Convention Center, Meeting Room 215
10:00 AM – 11:30 AM MDT
210: Galactic Ecosystems: Galaxy Structure and Evolution
10:00-10:25 AM
210.01 Andrew Harris (University of Maryland, College Park): Understanding our Galactic center with SOFIA
Abstract: This talk reviews some of the most important advances SOFIA has made to our understanding of our Galactic center. Instruments on SOFIA probed the mid- and far-infrared in continuum, spectral lines, and polarization, tracing energy deposition, physical conditions, and magnetic fields across the region. These have provided a vastly improved view of the 200 pc-wide Circum-Nuclear Zone (CMZ) containing material that orbits the nuclear core, and also of material close to the Galaxy's 4 million solar mass black hole. SOFIA observations have provided information crucial to understanding key interactions within this complex region. Deep at the bottom of the Galaxy's potential well, the Galactic center is home to extremes in stellar density, stellar properties, and energy density. Collisions and orbital shear regulate star formation in massive molecular clouds like nowhere else in the Galaxy. SOFIA studies tell us not only about processes and structures in our own Galaxy, but provide a level of detail unachievable in any other galaxy to help us understand galactic nuclei everywhere in the universe.
10:25-10:45 AM
210.02 Dario Fadda (SOFIA/USRA): The [CII] 158µm line emission in nearby Galaxies
Abstract: The 158.7um emission line from the singly ionized carbon is the brightest far-IR line emitted by galaxies, usually amounting to 1% or more of the total far-IR continuum. Since the line acts as the main cooling channel for photodissociation regions in the interstellar medium (ISM), it is essential to study the properties of the ISM in high redshift galaxies, as recently shown by ALMA observations. However, because of the low ionization potential of carbon, C+ exists in a variety of environments, from HII regions to warm molecular clouds. Moreover, mechanisms different than stellar emission can significantly contribute to the emission. It is therefore essential to study in detail the contribution of the different ISM regions and mechanism of emission of C+ in nearby galaxies to better infer the properties of the ISM in distant galaxies. We will show how Herschel and SOFIA observations of nearby extended galaxies have shed new light on the C+ emission origin and its relationship with star formation rates in galaxies.
10:45-11:00 AM
210.03 Christopher Hayward (Flatiron Institute): The effect of AGN on host-galaxy dust heating
Abstract: Theorists have recently started to examine the effects of AGN radiation on dust heating on host galaxy scales via performing dust radiative transfer on simulated AGN-hosting galaxies. We and others have found that in some cases, obscured AGN heating can dominate the galaxy-scale cold dust emission, even at rest-frame wavelengths >100 micron. I will summarize these results and discuss implications for using FIR emission as a star formation rate tracer.
11:00-11:10 AM
210.04 Randolf Klein (SOFIA/USRA): The Photodissociation and Ionization Fronts in M17-SW Localized with FIFI-LS on Board SOFIA
Abstract: To understand star formation rates, studying feedback mechanisms that regulate star formation is necessary. The radiation emitted by nascent massive stars play a significant role in feedback by photodissociating and ionizing their parental molecular clouds. To gain a detailed picture of the physical processes, we mapped the photodissociation region (PDR) M17-SW in several fine-structure and high-J CO lines with FIFI-LS, the far- infrared imaging spectrometer aboard SOFIA. An analysis of the CO and [O I]146 μm line intensities, combined with the far-infrared intensity, allows us to create a density and UV intensity map using a one-dimensional model. The density map reveals a sudden change in the gas density crossing the PDR. The strengths and limits of the model and the locations of the ionization and photodissociation front of the edge-on PDR are discussed.
11:10-11:20 AM
Ka Wai Ho (UW-Madison): The "stable" thermal unstable medium and its effect on cold filament in multi-phase ISM
Abstract: The ubiquity of very thin and lengthy cold neutral medium (CNM) has been reported by multiple authors in the H I community. Yet, the reason of how the CNM can be so long and lengthy is still in debate. In this paper, we recognize a new type of instability due to the attractive nature of the pressure force in the unstable phase. Furthermore, we demonstrate that the presence of turbulence can stabilize the originally unstable phase through its mixing effects. We provide a new estimation of the average CNM filament aspect ratio with the consideration of force balances at the phase boundary, which is roughly 5–20 in common CNM environment. We show that most of the cold filaments are less filamentary than what usually predicted via MHD turbulence theory or inferred from observations: The average length of CNM filament is roughly 1/2 of that in isothermal MHD turbulence with similar turbulence conditions. This suggests that the ‘cold filaments’ that are identified in observations might not be in pressure equilibrium or generated via other mechanisms.
2:00 PM – 3:30 PM MDT
223: New Worlds/Time Domain: Stars and Solar System
2:00-2:25 PM
223.01 Kathleen Kraemer (Boston College): Stellar Evolution through the Lens of SOFIA -- Highlights of Evolved Star Investigations
Abstract: Over the last decade, the astronomical community used the Stratospheric Observatory for Infrared Astronomy (SOFIA) to investigate nearly every phase of stellar evolution. Evolved stars, which have left the main sequence, were particularly well suited for study with the suite of instruments on SOFIA. Targets of such studies included asymptotic giant branch (AGB) stars, red supergiants, Wolf-Rayet stars, luminous blue variables, novae, post-AGB stars, planetary nebulae, and supernova remnants. These objects are actively shedding or have recently shed the bulk of their mass, and this newly enriched material will be recycled into the next generations of stars and planets. The grains and molecules that are forming in and around these evolved sources have a plethora of signatures in the infrared with which to trace the physical and chemical conditions of the gas and dust and that of the stars which produced them. This talk reviews some of the discoveries and new insights that came from observations with EXES, FIFI-LS, FLITECAM, FORCAST, GREAT, and HAWC+, advancing our understanding of evolved stars and stellar evolution. Many thanks to the SOFIA instrument teams, flight crews, and staff scientists for making these studies possible, including building the instruments, making the observations, and creating high-quality data products, and to the science teams whose work is reviewed here. SOFIA was jointly operated by the Universities Space Research Association, Inc. (USRA), under NASA contract NNA17BF53C, and the Deutsches SOFIA Institut (DSI) under DLR contract 50 OK 0901 to the University of Stuttgart.
2:25-2:45 PM
223.02 Robert Gehrz (University of Minnesota): Infrared Observations of Novae with SOFIA and Beyond
Abstract: Thermonuclear runaways (TNRs) on the surfaces of white dwarf (WD) stars accreting matter in close binary systems produce classical nova explosions that may play an important part in producing some of the isotopic anomalies that are present in the remnants of the primitive solar system. We review the use of infrared (IR) photometric and spectroscopic observations to quantify the physical parameters of classical nova outbursts and to assess their contributions to the interstellar medium (ISM) where star formation occurs. Metal abundances in the ejecta can be deduced from dust emission features and metallic forbidden line emission. The observations described here also provide basic information about the TNR that causes the nova explosion, the chemical composition of the WD upon which the TNR occurs, and the nature of the WD's progenitor star. We show that some recent bright novae have ejected shells that are extremely overabundant in C, N, O, Ne, Mg, Al, and Si. The properties of dust grains produced by novae are reviewed and compared to those of the dust grains observed in preplanetary nebulae and dust grains released from comet nuclei. By analogy to novae, supernovae (both Types I and II) and stellar mergers produce ejecta that enrich the ISM and contribute the building blocks of life and planets to new stellar and planetary systems. We review observations of novae made with the
Spitzer
Space Telescope and the NASA Stratospheric Observatory for Infrared Astronomy (SOFIA). We anticipate the impact that these observations will have on the definition of proposed FIR Probe missions, such as the PRobe far-Infrared Mission for Astrophysics (PRIMA), that will observe novae, stellar mergers, and supernova explosions.
2:45-3:10 PM
233.03 Dariusz Lis (Jet Propulsion Laboratory, California Institute of Technology): SOFIA Solar System Legacy
Abstract: I will present highlights of SOFIA studies of Solar System objects, including observations of water in the lunar south pole region, measurements of the D/H ratio in water in the atmosphere of Mars and in comets, as well as occultations of Pluto.
3:10-3:30 PM
223.04 Laura Lenkić (USRA): Building on SOFIA's Legacy: Future Prospects for Extragalactic Astronomy
Abstract: More than half of the energy output of galaxies is in the form of mid- to far-infrared radiation at 5-500 μm; consequently, the infrared is a tool of significant importance in our pursuit of understanding star formation and galaxy evolution. The Astro2020 Decadal Survey recognizes the importance of the infrared, as nearly half of the questions raised by the Decadal can be studied with the tools of infrared astronomy. In this talk, I will first review some of the scientific highlights of the Stratospheric Observatory for Infrared Astronomy (SOFIA) mission in the field of extragalactic astronomy, such as (among others) 1) how observations of local analogs to high-redshift galaxies enable studies of the dust, star formation, and star formation history properties of these systems, 2) how observations of high-redshift galaxies can help constrain the AGN and star forming contributions to far-infrared luminosity, and 3) how polarization observations at far-infrared wavelengths can reveal the geometry of the magnetic fields of galaxies and star forming regions, and help us understand how galaxies exchange metal enriched gas with their surrounding environment and the role of magnetic fields in star formation at the sub-parsec scale. Following this review, I will discuss how these SOFIA results pave the path for future important research areas in far-infrared extragalactic astronomy, including synergies with multi-messenger and time domain astronomy.
Wednesday, June 7
Albuquerque Convention Center, Meeting Room 215
10:00 AM – 11:30 AM MDT - 44
314: The Future of FIR Astronomy
10:00-10:20 AM
314.01 Michael Zemcov (Rochester Institute of Technology): Cold, Small, and Plentiful: the Future of Instrumentation for Far-IR Astrophysics
Abstract: Observations at far-infrared (FIR) wavelengths are critical to advancing our understanding in nearly all areas of astrophysics, from the search for habitable planets and the origin of life all the way back to the earliest stages of galaxy assembly. A developing portfolio of technologies, particularly in the field of spectrographic imaging, hold the promise of paradigm-shifting advances in scientific understanding. In this talk, I review the landscape of techologies of strategic importance to meeting the science goals in recent State-of-the-Field reports, examine the advancement of existing and new observing platforms, and discuss possible paths to best address the challenges facing far-infrared astronomy in this decade and beyond.
10:20-10:32 AM
314.02 Jason Glenn (NASA GSFC): PRIMA: the PRobe far-Infrared Mission for Astrophysics
Abstract: PRIMA is a far-infrared observatory concept being developed to address timely and fundamental questions about the growths of galaxies and solar systems and their constituents. It will observe the build-up of stars, black holes, and dust in galaxies over cosmic time, and trace the masses and water contents of protoplanetary disks to probe the growths of solar systems. The majority of observing time will be devoted to Guest Observer programs, with focused PI programs to address key science to inform community planning. PRIMA will have spectral, hyperspectral imaging, and polarimetric capabilities, enabled now for the first time by extraordinary progress in kinetic inductance detector (KID) array technology over the last two decades. The telescope will be cooled to 5 K to take maximum advantage of the KID sensitivities. For observations of atomic fine-structure lines, molecular lines, and solid-state emission and absorption bands, R = 130 spectral coverage will range from approximately 24 microns to 240 microns, with a high-resolution mode across the entire band that will have a spectral resolving power of a few thousand at 100 microns. R ~ 10 moderate-resolution (hyperspectral) imaging will range from 25 to 80 microns for rest-frame, mid- and far-infrared spectral energy distribution measurements to disambiguate star formation and active galactic nuclei in galaxies and to probe dust grain composition. Polarimetric observations from 80 to ~200 microns will bridge between the large-scale polarimetry of the interstellar medium from cosmic microwave background observatories and protostellar disk-scale interferometric observations to probe magnetic fields at the critical scales at which clouds collapse to form stars. An overview of PRIMA’s basic design and capabilities will be presented.
10:32-10:44 AM
Christopher Walker (University of Arizona): Single Aperture Large Telescope for Universe Studies (SALTUS)
Abstract: SALTUS (Single Aperture Large Telescope for Universe Studies) is a Probe mission concept that employs a radiatively cooled, 20 meter inflatable aperture and cryogenic detectors to better understand our cosmic origins and the possibility of life elsewhere. The science objectives of SALTUS are to: 1) Trace astrochemical signatures of planet formation, habitable zones, and life. 2) Trace galaxy evolution and heavy element production over cosmic time. 3) Perform a census and probe the structure of supermassive black holes. To achieve these objectives SALTUS will perform spectroscopic studies towards 100’s of exoplanets, protoplanetary disks, galaxies, and solar system objects over a wavelength range from ~30 to 300 microns at high and moderate spectral resolution. The focal plane will include both coherent and incoherent detectors cooled by a closed-cycle refrigeration system. The telescope will employ a sunshield and be radiatively cooled to ~45K. SALTUS will have ~10x the collecting area of JWST and ~30x that of Herschel. The 20 meter aperture of SALTUS will be used as a space node for millimeter-wave VLBI observations of massive black holes in the Milky Way and beyond. The mission is designed to provide a lifetime of > 5 years. More than 50% of its on-orbit time will be dedicated to the SALTUS Guest Observer (GO) Program. With its large aperture and suite of instruments, SALTUS will provide a quantum leap in our understanding of the universe.
10:44-10:56 AM
314.04 Asantha Cooray (University of California, Irvine): TBD
10:56-11:30 AM
Panel Discussion led by Erick Young (USRA)