GLIMPSE (Galactic Legacy Infrared Mid-Plane Survey Extraordinaire)
GLIMPSE is Spitzer Legacy project, that delivers data to the Spitzer Science Center (SSC). The GLIMPSE I (aka GLIMPSEI), GLIMPSE II (aka GLIMPSEII), GLIMPSE 3D (aka GLIMPSE3D), GLIMPSE360, Vela-Carina, DeepGLIMPSE, GLIMPSE Proper, APOGLIMPSE, SMOG, and Cygnus-X deliveries all contain a "Catalog" and an "Archive", all are served through IRSA's General Catalog Query Tool, Gator. The GLIMPSEI source lists are from the 20070412 "FINAL" (DR5) data delivery; the GLIMPSEII source lists are from the "final" data delivery on 20080418 and the December 2008 and November 2009 single epoch catalog deliveries; the GLIMPSE3D source lists are concatinated from five delivery dates: 20070717, 20080130, 20080721, 20090106, 20091102. GLIMPSEI, GLIMPSEII and GLIMPSE3D images are served through IRSA's general search service Atlas.
GLIMPSEI
The GLIMPSEI Catalog and Archive contain sources for the entire GLIMPSEI Survey (l=10-65 deg, 295-350 deg, b=+- 1 deg) plus the Observation Strategy Validation (OSV) region at about l=284 deg. The SSC pipeline version used for the GLIMPSEI v2.0 source lists is mostly S13.2 (corrected for the jailbar effect), with an occasional re-observation processed with SSC pipeline version S14 or later.
NOTE: For source lists from l=10 to 11 and l=349 to 350 deg please select the GLIMPSEII dataset, not the GLIMPSEI dataset.
GLIMPSEII
The GLIMPSEII Catalog and Archive contain sources for the entire GLIMPSEII Survey region. The nominal GLIMPSEII Survey region is l= -10 deg to 10 deg (details in table below). These data products include all epochs of the GLIMPSE II survey region. They also include the Galactic center data from the General Observer (GO) program GALCEN (PI: Stolovy, Program ID=3677 search Spitzer Data at IRSA), as well as GLIMPSE I data at the boundary of the surveys (at l=10 deg and l=349 deg).
longitude (deg) | latitude (deg) |
5<l<10 and 350<l<355 | -1<b<1 |
2<l<5 and 355<l<358 | -1.5<b<1.5 |
0<l<2 and 358<l<360 | -2<b<2 |
NOTE: For source lists from l=10 to 11 and l=349 to 350 deg please select the GLIMPSEII dataset, not the GLIMPSEI dataset.
GLIMPSE3D
GLIMPSE 3D Archive Notice: In June 2009, an error in IRSA's copy of the GLIMPSE 3D Archive was corrected. The affected sky coverage is l = 333-337 degrees; b = -1 to -3 degrees. 883,569 rows from the original Archive delivery were incorrectly excluded from the database, and replaced by 443,320 rows from the GLIMPSE 3D Catalog. This error affects users of the GLIMPSE 3D Archive prior to June 2009.
The GLIMPSE3D Catalog and Archive contain sources from five cumulative deliveries (DR1, DR2, DR3, January 2009, and November 2009 from 2007-2009) from GLIMPSE 3D. GLIMPSE3D adds vertical extensions, generally up to |b| < 3deg, but up to |b| < 4.2deg in the center of the Galaxy. The goal of this coverage is to provide data to study the vertical stellar and interstellar structure of the inner Galactic disk, bar, and spiral arms.
GLIMPSE360
The GLIMPSE360 Catalog and Archive contain sources from the three cumulative deliveries, covering Galactic longitudes l=65.0-265.0 deg., excluding l=102-109deg (SMOG) and l=76-82deg (Cygnus-X). Even though bands 3 & 4 are not used in the Spitzer Warm Mission, the fields are included in the GLIMPSE360 source lists, filled in by null values.
Vela-Carina
The Vela-Carina Catalog and Archive contain sources from longitudes l=255-295d.
DeepGLIMPSE
The DeepGLIMPSE Catalog and Archive contain sources from longitudes l=265-350d and l=25-65d. DeepGLIMPSE increases the dynamic range over GLIMPSE, GLIMPSE3D, and Vela-Carina by a factor of 13 on the faint end and a factor of 3 on the bright end. Approximately 43% of the DeepGLIMPSE observations are of areas not previously observed. Even though bands 3 & 4 are not used in the Spitzer Warm Mission, the fields are included in the DeepGLIMPSE source lists, filled in by null values.
GLIMPSE Proper
The GLIMPSE Proper Catalog and Archive contain sources from l=0-5.2 deg, 354.8-360.0 deg. The data were taken with 2 second frametime exposures and there are nominally 3 visits on the sky. Data processed by SSC pipeline processing version S19.2.0 were used to make the source lists. The format for the GLIMPSE Proper source lists is the same as the previous GLIMPSE (GLIMPSEI, GLIMPSEII, GLIMPSE3D, Vela-Carina, GLIMPSE360, Deep GLIMPSE) source lists. Even though bands 3 (5.8 um) & 4 (8 um) are not used in the Spitzer Warm Mission, the fields are included in the GLIMPSE Proper source lists, filled in by null values.
APOGLIMPSE
The APOGLIMPSE Catalog and Archive contain sources from 53 sq. deg. (14 fields) of the inner Galactic plane, |l|=5-46d, that were also targeted by the APOGEE/APOGEE-II surveys. For two of the 14 fields, closest to the Galactic center, there are three 1.2 second exposures at each position at Galactic longitudes l=5d to 6.5d and l=354d to 355d; b=-1d to +1d. These two innermost fields extend the Galactic center coverage of GLIMPSE Proper with the same style of coverage. For the remaining 12 areas, there are three High Dynamic Range (HDR) mode (10.4 second and 0.4 second) exposures at each position at Galactic longitude areas within l=9d to 46d and l=316d to 351d; b=-1d to +1d. Data processed by SSC pipeline processing version S19.2.0 were used to make the source lists. The format for the APOGLIMPSE source lists is the same as the previous GLIMPSE (GLIMPSEI, GLIMPSEII, GLIMPSE3D, Vela-Carina, GLIMPSE360, Deep GLIMPSE, GLIMPSE Proper) source lists. Even though bands 3 (5.8 um) & 4 (8 um) are not used in the Spitzer Warm Mission, the fields are included in the APOGLIMPSE source lists, filled in by null values.
SMOG
The SMOG Catalog and Archive contain sources from longitudes l=102-109d.
Cygnus-X
The Cygnus-X Catalog and Archive contain sources from longitudes l=76-82d extracted from data processed using the GLIMPSE pipeline. The same data has also been processed by the Cygnus-X Legacy team.
Catalog vs Archive (More Reliable vs More Complete)
The Catalog is a more reliable list of sources, and the Archive is a more complete list both in number of sources and flux measurements at each wavelength (less nulling of fluxes). The main differences between the Catalog and Archive are 1) fluxes brighter than a threshold that marks a nonlinear regime are nulled (removed) in the Catalog; 2) sources within 2.0 arcsec of another are culled (removed) from the Catalog, whereas the Archive allows sources as close as 0.5 arcsec from another; 3) sources within the PSF profile of a saturated source are culled from the Catalog but not the Archive; and 4) the Catalog has higher signal-to-noise thresholds and slightly more stringent acceptance criteria (e.g., number of detections in various bands). The IRAC data were bandmerged with the 2MASS All-Sky Point Source Catalog. See the GLIMPSEI v2.0, GLIMPSEII v2.1, GLIMPSE3D v1.4, GLIMPSE360 v1.5, Vela-Carina v1.0, DeepGLIMPSE v1.3, GLIMPSE Proper v1.0, APOGLIMPSE v1.0, SMOG v1.1, and Cygnus-X v1.0 documents from the Data Products Document Repository for more details. There are about 31.2 million sources in the GLIMPSEI Catalog and about 49.2 million in the GLIMPSEI Archive. There are about 19.1 million sources in the GLIMPSEII Catalog and about 24.4 million sources in the GLIMPSEII Archive. There are about 20.4 million sources in the GLIMPSE3D Catalog and about 32.2 million sources in the GLIMPSE3D Archive. There are about 42.6 million sources in the GLIMPSE360 Catalog and about 49.4 million sources in the GLIMPSE360 Archive. There are about 2 million sources in the Vela-Carina Catalog and about 4.5 million sources in the Vela-Carina Archive. There are about 38.2 million sources in the DeepGLIMPSE Catalog and about 63.5 million sources in the DeepGLIMPSE Archive. There are about 11.5 million sources in the GLIMPSE Proper Catalog and 16.4 million sources in the GLIMPSE Proper Archive. There are about 8.3 million sources in the APOGLIMPSE Catalog and 20.6 million sources in the APOGLIMPSE Archive. There are about 2.5 million sources in the SMOG Catalog and about 2.8 million sources in the SMOG Archive. There are about 3.9 million sources in the Cygnus-X Catalog and about 4.4 million in the Cygnus-X Archive.
Catalog and Archive Fields and FlagsEach entry in the GLIMPSE I, II, 3D, 360, Vela-Carina, DeepGLIMPSE, GLIMPSE Proper, APOGLIMPSE, SMOG, and Cygnus-X Catalogs and Archives have the following information:
designation -> SSTGLMC GLLL.llll±BB.bbbb, SSTGLMA GLLL.llll±BB.bbbb 2MASS PSC names -> 2MASS designation, 2MASS counter position -> l, b, dl, db, ra, dec, dra, ddec flux -> magi, di_m, fi, dfi, rms_fi (IRAC); mag_t, dt_m, ft, df_t (2MASS) diagnostic -> sky_i, sn_i, dens_i, # detections mi out of ni possible (IRAC); sn_t (2MASS) flags -> Close Source Flag (csf), Source Quality Flag (sqf_i), Flux Method Flag (mfi) (IRAC); Source Quality Flag (sqf_t) (2MASS)
where i is the IRAC wavelength number (IRAC bands 1 - 4) (3.6 µm, 4.5 µm, 5.8 µm and 8.0 µm) and t is the 2MASS wavelength bands (J, H, Ks).
Details of the fields are as follows. Note that IRSA's General and Basic Catalog Search Tools (Gator and BabyGator) calculate colors, using magnitude measurements in the GLIMPSE source lists. For more information on these Gator-derived columns, click here.
The 'designation' entry can have the following set of information:
Archive=> SSTGLMA GLLL.llll+-BB.bbbb Catalog=> SSTGLMC GLLL.llll+-BB.bbbb
This is the object designation or name as specified by the IAU recommendations on source nomenclature. It is derived from the coordinates of the source, where G denotes Galactic coordinates, LLL.llll is the Galactic longitude in degrees, and ±BB.bbbb is the Galactic latitude in degrees. The coordinates are preceded by the acronym SSTGLMC (GLIMPSE Catalog) or SSTGLMA (GLIMPSE Archive). For Vela-Carina, the prefixes are SSTVELC and SSTVELA respectively. For DeepGLIMPSE, the prefixes are SSTGLMDPC and SSTGLMDPA respectively. For GLIMPSE Proper, the prefixes are SSTGLMPRC and SSTGLMPRA respectively. For APOGLIMPSE, the prefixes are SSTAPOGLC and SSTAPOGLA respectively. For SMOG, the prefixes are SSTSMOGC and SSTSMOGA respectively. For Cygnus-X, the prefixes are SSTCYGXC and SSTCYGXA respectively.
Designation is:
SST = Spitzer Space Telescope GLM = GLIMPSEI, GLIMPSEII, GLIMPSE3D, or GLIMPSE360 projects or VEL = Vela-Carina project
or GLMDP = DeepGLIMPSE project or GLMPR = GLIMPSE Proper project or APOGL = APOGLIMPSE project or SMOG = SMOG project or CYGX = Cygnus-X project A = more complete Archive C = highly reliable Catalog G = Galactic coordinates LLL.llll = Galactic longitude (degrees) of the source +-BB.bbbb = Galactic latitude (degrees) of the source
The 2MASS designation is the source designation for objects in the 2MASS All-Sky Release Point Source Catalog. It is a sexagesimal, equatorial position-based source name of the form hhmmssss±ddmmsss, where hhmmssss is the right ascension (J2000) coordinate of the source in hours, minutes and seconds, and ±ddmmsss is the declination (degrees, minutes, seconds). The 2MASS counter is a unique identification number for the 2MASS PSC source.
There are 8 'position' related fields:
l, b, dl (error), db (error), ra, dec, dra (error), ddec (error)
The position is given in both Galactic (l,b) and equatorial (RA, Declination) J2000 coordinates, along with estimated uncertainties. The pointing accuracy is 1 arcsec (Werner et al. 2004). The SSC pipeline does pointing refinement of the images based on comparison with the 2MASS Point Source Catalog, whose absolute accuracy is typically <0.2 arcsec (Cutri et al. 2005). After applying the SSC geometric distortion corrections and updating to the 2MASS positions, the GLIMPSE point source accuracy is typically 0.3 arcsec absolute accuracy, limited by undersampling of the point-spread function. The position uncertainties are calculated by the bandmerger based on the uncertainties of individual detections, propagated through the calculation of the weighted mean position.
The following are 'flux' related fields:
magi & mag_t, di_m & dt_m (error), fi & f_t, dfi & df_t (error), rms_fi
For each IRAC band i = 3.6, 4.5, 5.8, and 8.0 µm and, when available 2MASS band t = J, H, and Ks, the fluxes are expressed in magnitudes (magi, mag_t) and in mJy (fi, f_t). Each IRAC flux is the error-weighted average of all independent detections of a source. The 2MASS magnitudes and uncertainties are from the 2MASS All-Sky Release Point Source Catalog. They are the j_m, j_msigcom, h_m, h_msigcom, and k_m, k_msigcom columns from the 2MASS PSC. The zeropoints for converting from flux to magnitude for the S13.2 and later SSC processing versions are from Reach et al. (2005) for the IRAC bands and Cohen et al. (2003) for 2MASS and given in Table 1 below. Note, all the fluxes have the same zero points as they are on the same calibration (v2 GLIMPSEI & GLIMPSEII, GLIMPSE3D, GLIMPSE360, Vela-Carina, DeepGLIMPSE, GLIMPSE Proper, APOGLIMPSE, SMOG, Cygnus-X).
Table 1. Zeropoints for Flux to Magnitude Conversion Band J H K [3.6] [4.5] [5.8] [8.0] GLIMPSEI Zeropoints (Jy) 1594 1024 666.7 280.9 179.7 115.0 64.13
The IRAC flux/magnitude uncertainties (dim; dfi) are computed during the photometry stage and take into account photon noise, readnoise, goodness of flat fielding, and PSF fitting (Stetson 1987).
The rms deviation (rms_fi) of the individual detections from the final flux of each source is provided.
The 'flux diagnostics' related fields are:
sky_i, sn_i, sn_t, dens_i, # detections mi out of ni possible
The associated flux diagnostics are a local background level (sky_i) (i = 3.6, 4.5, 5.8, and 8.0 µm) in MJy/sr, a Signal/Noise (sn_i), a local source density (dens_i) (number of sources per square arcmin), and number of times (mi) a source was detected out of a calculated possible number (ni). The Signal/Noise is the flux (f_i) divided by the flux error (dfi). The Signal/Noise for the 2MASS fluxes (sn_t) have been taken from the 2MASS PSC (the j_snr, h_snr and k_snr columns). The local source density is measured as follows: The individual IRAC frame is divided into a 3×3 grid, each of the nine cells being 1.71 arcmin x 1.71 arcmin. A source density is calculated for each cell (number of sources per arcmin^2), and is assigned to each source in that cell. The local source density can be used to assess the confusion in a given region, along with the internal reliability. mi and ni can be used to estimate reliability. ni is calculated based on the areal coverage of each observed frame; due to overlaps some areas are observed more than twice per band.
There are three types of flags: the Close Source Flag, the Source Quality Flag and the Flux Calculation Method Flag. The Close Source Flag is set if there are Archive sources that are within 3 arcsec of the source. The Source Quality Flag provides a measure of the quality of the point source extraction and bandmerging. The Flux Calculation Method Flag describes how the final Catalog/Archive flux was determined.
- The Close Source Flag (csf) is set when a source in the Archive is within 3.0 arcsec of the source. It was found that the magnitudes of a source with nearby sources closer than about 2 arcsec are not reliably extracted and bandmerged. A source that has Archive sources within 2.0 arcsec of the source are culled from the Catalog. A source that has Archive sources within 0.5 arcsec of the source are culled from the Archive. The flag is defined as follows:
0 no sources in the Archive within 3" of the source 1 sources in the Archive between 2.5" and 3" of the source 2 sources in the Archive between 2.0" and 2.5" of the source 3 sources in the Archive between 1.5" and 2.0" of the source 4 sources in the Archive between 1.0" and 1.5" of the source 5 sources in the Archive between 0.5" and 1.0" of the source 6 sources in the Archive within 0.5" of the source
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The Source Quality Flag (sqf) is generated from SSC-provided masks and the GLIMPSE pipeline, during point source extraction on individual IRAC frames and bandmerging. Each source quality flag is a binary number allowing combinations of flags (bits) in the same number. Flags are set if an artifact (e.g., a hot or dead pixel) occurs near the core of a source - i.e. within 3 pixels. A non-zero SQF will in most cases decrease the reliability of the source. Some of the bits, such as the DAOPHOT tweaks, will not compromise the source s reliability, but has likely increased the uncertainty assigned to the source flux. If just one IRAC detection has the condition requiring a bit to be set in the SQF, then the bit is set even if the other detections did not have this condition. Sources with hot or dead pixels within 3 pixels of source center (bit 8), those in wings of saturated stars (bit 20), and those within 3 pixels of the frame edge (bit 30) are culled from the Catalog.
Table 2 gives the Source Quality Flag bits and origin of the flag (SSC or GLIMPSE pipeline). Each of the 5 bands has its own Source Quality Flag. For the cross-band confusion flag and the cross-band merge lumping flag, when the condition is met for one of the bands, the bit is set for all the source's bands.
The value of the SQF is sum{2^{(bit-1)}}. For example, a source with bits 1 and 4 set will have SQF = 2^0 + 2^3 = 9. If the SQF is 0, the source has no detected problems. More information about these flags and a bit value key can be found in Appendix B of the delivery document.
Source Quality Flag (SQF) Bits SQF bit Flag Description Source 1 poor pixels in dark current SSC 2 flat field applied using questionable value SSC 3 latent image SSC 3 persistence (p) 2MASS 4 photometric confusion (c) 2MASS 7 muxbleed correction applied GLIMPSE *8 hot, dead or otherwise unacceptable pixel SSC,GLIMPSE 9 muxbleed correction applied is > 3-sigma above bkg GLIMPSE 9 electronic stripe (s) 2MASS 10 allstar tweak positive GLIMPSE 11 allstar tweak negative GLIMPSE 13 confusion in in-band merge GLIMPSE 14 confusion in cross-band merge (IRAC) GLIMPSE 14 confusion in cross-band merge (2MASS) GLIMPSE 15 column pulldown correction GLIMPSE 16 banding correction GLIMPSE 19 data predicted to saturate GLIMPSE *20 saturated wing area GLIMPSE *20 diffraction spike (d) 2MASS 21 pre-lumping in in-band merge GLIMPSE 22 post-lumping in cross-band merge (2MASS) GLIMPSE 23 photometry quality flag 2MASS 24 photometry quality flag 2MASS 25 photometry quality flag 2MASS *30 edge of frame (within 3 pixels of edge) GLIMPSE
For 2MASS data, the following flags from the 2MASS All-Sky PSC are mapped into bits 3,4,20 and 9 in the source quality flag see 2MASS Documentation for more information about these 2MASS flags. Users should consult the 2MASS All-Sky Point Source Catalog for the complete information about the source, including all of their quality flags.
2MASS Flag => SQF ---------- --- "p" persistence latent (bit 3) "c" photom confusion corr sat star wing (bit 4) "d" diffraction spike uncorrectable sat star (bit 20) "s" electronic stripe muxbleed (bit 9)
The 2MASS photometric quality flag was mapped onto the Source Quality Flag as follows:bits 23, 24, 25 Photometric quality flag 2MASS SQF bits "ph" Flag => 23, 24, 25 value ------------- --------------- ---------- X 0 0 0 0 U 1 0 0 4194304 F 0 1 0 8388608 E 1 1 0 12582912 D 0 0 1 16777216 C 1 0 1 20971520 B 0 1 1 25165824 A 1 1 1 29360128 where X - There is a detection at this location, but no valid brightness estimate can be extracted using any algorithm. U - Upper limit on magnitude. Source is not detected in this band or it is detected, but not resolved in a consistent fashion with other bands. F - This category includes sources where a reliable estimate of the photometric error could not be determined. E - This category includes detections where the goodness-of-fit quality of the profile-fit photometry was very poor, or detections where psf fit photometry did not converge and an aperture magnitude is reported, or detections where the number of frames was too small in relation to the number of frames in which a detection was geometrically possible. D - Detections in any brightness regime where valid measurements were made with no [jhk]_snr or [jhk]_cmsig requirement. C - Detections in any brightness regime where valid measurements were made with [jhk]_snr>5 AND [jhk]_cmsig<0.21714. B - Detections in any brightness regime where valid measurements were made with [jhk]_snr>7 AND [jhk]_cmsig<0.15510. A - Detections in any brightness regime where valid measurements were made with [jhk]_snr>10 AND [jhk]_cmsig<0.10857.
bit values: bt 1 => 1; 2 => 2; 3 => 4; 4 => 8; 5 => 16; 6 => 32; 7 => 64; 8 => 128 bt 9 => 256; 10 => 512; 11 => 1024; 12 => 2048; 13 => 4096; 14 => 8192; 15 => 16384; bt 16 => 32768; 17 => 65536; 18 => 131072; 19 => 262144; 20 => 524288; bt 21 => 1048576; 22 => 2097152; 23 => 4194304; 24 => 8388608; 25 => 16777216; 30 => 536870912 * Note that sources with flags 8, 20, and 30 have already been removed from Catalog or the magnitude nulled.
-
Flux calculation Method Flag (mfi) indicates by bit whether a given frametime was present, and whether that frametime was used in the final flux. Table 3 below defines the values for this flag for v2.0 GLIMPSEI: value= 2^(present bit - 1) + 2^(used bit - 1).
Table 3.
Method Flag (MF) for v2.0 GLIMPSE I: exp present bit used bit 0.6 1 2 2 3 4 12 5 6 30 7 8 100 9 10
Table 4 below defines the values for this flag for v2.0 GLIMPSEII, GLIMPSE3D, GLIMPSE360, Vela-Carina, DeepGLIMPSE, GLIMPSE Proper, APOGLIMPSE, SMOG, and Cygnus-X:Table 4.
Method Flag (MF) for v2.0 GLIMPSEII, GLIMPSE3D, GLIMPSE360, Vela-Carina, DeepGLIMPSE, GLIMPSE Proper, APOGLIMPSE, SMOG, and Cygnus-X: ft present used bit (value) bit (value) 0.6 1 (1) 2 (2) 1.2 3 (4) 4 (8) 2 5 (16) 6 (32) 12 7 (64) 8 (128) 30 9 (256) 10 (512) 100 11 (1024) 12 (2048)
This flag is more useful for High Dynamic Range (HDR) mode data which has two frametimes, one of which is not necessarily used (i.e. the 12 second frametime data is not used for the very bright sources). For example: for 2 second frametime data, the method flag always equals 12 (2^2 + 2^3). If 0.6 and 12 sec frametime data were present, but only the 12 sec data were used, then bits 1 and 7 will be set (fluxes present) and bit 8 will be set (12 sec used) and the MF will be 2^0 + 2^6 + 2^7 = 1 + 64 + 128 = 193 (see Table 4). Note that, in practice, MF of 193 is rarely assigned because some detections are thrown out at the beginning of bandmerging because of sensitivity or saturation issues.
For GLIMPSE360 12/0.6 sec frametime HDR mode, the relevant numbers work out to be3 - short exp data used, long exp data absent 67 - short used, long present but unused 192 - long exp used, short absent 193 - long exp used, short present but unused
REFERENCES
Cohen, M., Wheaton, W.A., and Megeath, S.T. 2003, AJ, 126, 1090 Cutri, R. et al. 2005 Reach, W. et al. 2005, PASP, 117, 978. Stetson, P. 1987, PASP, 99, 191. Werner et al. 2004, ApJS, 154, 1.