SPHEREx Data Explorer at IRSA: Other Searches

Contents of page/chapter:
+Introduction & Terminology
+Interactive Target Refinement
+TAP Searches: More about constraints
+ObsCore Searches: More kinds of constraints
+TAP Search
+ObsCore Search
+VO SCS -- VO Simple Cone Search
+NED Objects -- Searching for NED objects

Introduction & Terminology

• VO = Virtual Observatory
• TAP = table access protocol . TAP services enable complex queries of tables using ADQL.
• ADQL = astronomical data. query language
• ObsCore = core components of Observation Data Model
• Data model = A standard logical structure for a type of dataset; more flexible and general than a data format.
• ObsTAP = TAP service that serves ObsCore tables

The SPHEREx Data Explorer can help you interactively create ADQL which then you can copy and use in your own code elsewhere.

By using TAP and ObsTAP queries, you can use IRSA services to talk to other archives that also comply with these standards, world-wide.

The first several parts of this section talk more generally about interactive target refinement and constraints that are common to more than one of the searches discussed here. Specifics of particular searches follow after that.

Interactive Target Refinement

When you click on the icon you bring up a window:

If you have entered a target already, the window arrives already centered on the target. If not, it is centered on the galactic center, zoomed out. If you have entered a cone search radius already, then the circle drawn on the image is that cone size. You can manipulate this image with the same basic tools as in the visualization tools.

To change the search region interactively, choose the selection tools and draw a shape on the image. Note that if you have selected a cone search on the left, no matter what you select on the right, it will give you a cone search. If you change the cone position or radius in the yellow boxes after you change the selection, it will update the region in the image.

If you want to quit out of the selection without changing, click on "end selection" (the brown text near the top of the image).

If you select polygon on the left, and you use the selection tool for "cone selection" on the right, you will get a spherical polygon (a polygon where the line segments are on a sphere).

When you are done with this pop-up window, click on the 'x' in the upper right of the window. Then you can continue with whatever you were doing before you started to refine your target parameters.

TAP Searches: Constraints

You can have several different ways of constraining your search depending on the options you have selected before the "Enter Constraints" section, and sometimes the options depend on what kind of service is available at the TAP service you have selected. If the options do not appear initially, click on the downward arrow to "unfold" the options.

Enter Constraints: Spatial

This part of the interface allows you to specify the details of a spatial search. You need to specify both what kind of search you want to do and which columns of the catalog are to be used for coordinates.

This is what it looks like when you do a single target cone search; note that you have the same name resolution options as in any other search here.

And, this is what it looks like when you do a single target polygon search. The search areas here (visible, selection, and custom) are the same as when you do a polygon search on catalog -- that is, you can select whether you want the catalog request to match the entire area of the image you have selected ("image"), or just the portion of the image you can see in the current view ("visible"), or your own ("custom") area. The list of vertices in the coordinates box are in decimal RA and Dec in degrees. You must enter at least 3 and at most 15 vertices, separated by a comma. You can also click on this icon to interactively refine your search position.

If you want to perform a multi-target search, click on "multi-object", which automatically brings up this pop-up, from which you can load a table from disk ("Upload tables" tab) or select one of the tables you have already loaded into the tool (click on the "Loaded tables" tab). Your uploaded catalog has to follow all the same rules as normal catalogs from disk.

After you find your file with your listed positions and upload it, the tool attempts to guess which two columns are the position columns. In this example, it has (correctly) guessed that the position columns are "ra" and "dec". If it guesses wrong, or can't figure it out, you can help it along by clicking on the down-arrow to 'expand' that part of the panel and selecting the two coordinate columns to use.

Regardless of what configuration you use, the last thing to check is which columns the tool has assumed are the position columns in the catalog to be matched to your position, region, or list of positions. Again, it attempts to make an educated guess as to the right columns, but if it guesses wrong, you can help it along by clicking on the down-arrow to 'expand' that part of the panel and selecting the two coordinate columns to use.

Enter Constraints: Temporal

This part of the interface allows you to specify which column of the catalog is to be used for timing, and allows you to constrain the date in two different systems.

This is what the panel looks like initially, where you specify the column in the catalog you are searching with the time and then the dates. If you don't remember what the column is in the catalog, click on the magnifying glass to get a pop-up with a list of all of the columns.
For the dates and times, if you click on the calendar icon at the far right of the entry box, you get a pop-up from which you can specify the date and time, shown here.
If you would like to work in MJD instead of ISO dates, select the "MJD" radio button. Note that it echoes below the box what it thinks you've entered in two different systems (UTC and MJD) to verify what you have entered.

Enter Constraints: Object ID

This part of the interface allows you to match object IDs.

This is what the panel looks like initially:
This is what the panel looks like after you have selected your uploaded list of IDs (in this case, a file called "table_Objects_1.tbl", which consists of an IPAC table file that turns out to be the results of an Inspect Objects search, which contains the object_id field), and it is being matched against the euclid_q1_phz_photo_z catalog, where the relevant field is "object_id".

⚠ Tips and Troubleshooting

• The names have to match exactly, so if one of the fields is a long integer, the IPAC table file to which you are comparing must also cast the ID as a long. (Computers are painfully stupid! You can't have one be a string and one be a longint.)
• If the catalog to which you are matching is not indexed by the name column you are using, the search may take a long time.
• If you are doing, say, an object ID search, you need to turn off the position search, otherwise it doesn't understand what you want it to do.

ObsCore Searches: More kinds of constraints

These are several additional ways of constraining your search depending on the options you have selected before the "Enter Constraints" section. These options most often appear if you have configured an ObsCore search. If all of these options do not appear initially, click on the downward disclosure arrow to "unfold" the options.

Enter Constraints: Observation Type and Source

This panel provides a way to constrain the: Calibration level - 0 is the least processed and 4 is the most processed, and not all instruments provide all levels Data product type - image, cube, spectrum, SED, time series, visibility, event, measurement, or none specified. You can select more than one of these at a time by using a right mouse click. Instrument name - must match exactly, wild cards not accepted Collection - must match exactly, wild cards not accepted

Enter Constraints: Location

This panel provides a way to constrain the location of your search. Here, it is a single object search, which works just like it does above, including the interactive target refinement via the bullsye icon. You can also upload a list of targets by selecting "multi-object" -- it brings up the same pop-up as above, from which you can load a table from disk ("Upload tables" tab) or select one of the tables you have already loaded into the tool (click on the "Loaded tables" tab). Your uploaded catalog has to follow all the same rules as normal catalogs from disk.

You can specify via the drop-down the type of your query: "observation boundary contains point", "observation boundary contains shape", "observation boundary is contained by shape", "observation boundary intersects shape", and "central point (s_ra, s_dec) is contained by shape." The latter refers to the columns "s_ra" and "s_dec" in the ObsTAP table.

Enter Constraints: Timing

	This panel provides a way to constrain the observation time of your search. This is the default option, where you want data completed in the last x hours (or other unit of time).
	This is the alternate option, where you want data overlapping a specified date range, where you can specify UTC or MJD times.

Enter Constraints: Spectral Coverage

	This panel provides a way to constrain the spectral coverage of your search. This is the default option, where you want data containing a given wavelength.
	This is the alternate option, where you want data overlapping a specified wavelength range.

TAP Search

When you first go to this tab, you will see this near the top of your screen:

At the top, you now have a choice of which TAP service you want to use, and it defaults to IRSA's. You can select your favorite from the list, or use the toggle on the left to enter your own custom URL. If you want to hide this top row after setting it (to, say, regain screen real estate), look for this on the far right:

the "TAP Services:" button (show/hide) will reveal or conceal this top row.

The rest of this search screen is basically identical to that which you get from the TAP Search described above, even if you pick a TAP service other than IRSA's (with a few exceptions, including if it's ObsCore; next section).

You can then select which table, or table collection and then table, you'd like to search from the pull-down menus.

For VizieR's services in particular, because there are so many tables, the tool will give you a slightly different interface under the "Tables" section of the window. Here is the default Vizier choices as of this writing:

Note that it tells you how many tables and rows are available. Switching to tables associated with journal articles, far more tables are available:

Now, if you click on the second tier menu (J/AJ/100/1091/table9), you get a pop-up, which is another Firefly table like any other in this tool, so it's searchable and sortable:

which makes it trivially easy to find tables in which you are interested, such as those associated with papers by Massey, as shown. Select the table that you want to search, and then continue to specify the rest of your search, just as described above in the TAP Search screen discussion.

The result of any TAP search is a catalog that can be interacted with like any other catalog in this tool.

⚠ Tips and Troubleshooting

• All the drop-downs near the top are roughly searchable. This is very useful if you are trying to find a particular table or service that you can't quite recall. Click in the drop-down area, type the first letter of what you are looking for, and it will jump to the first instance of a string starting with that letter. Hit that letter again, and it goes to the second instance of a string starting with that letter.
• Not every table available via this interface even has RA/Dec or, if it does, it may not be searchable via positions. If you have selected a table that doesn't have positions, it will not yield results if you try to search by position.
• If none of the columns are selected, then the tool behaves as if you have selected all of the columns.
• There is a maximum number of returned rows at the bottom. If you are anticipating more than this number of rows, increase this number!
• All of these searches are managed in the Job Monitor. If you are submitting a lot of jobs, keeping track of which job is which in list in the Job Monitor or in the myriad resulting tabs can be difficult. Using the "Title" input field, you can change the title by which the search will be listed in the Job Monitor, and in the title of the returned tab. You don't have to change it from the default to be able to search, however. (Once you change it, though, all subsequent searches you make will still have that same title.)
• If you arrive at the advanced ADQL page from the "Populate and edit ADQL" button, this is a one-way trip -- any changes you make to the ADQL here are NOT transmitted automatically back to the "UI Assisted" query page.

ObsCore Search

To launch an ObsCore search, you need to find a server that supports an ObsTAP search, and flip the corresponding toggle on the left, for example:

The "UI Assisted"/"Edit ADQL" switch at the top right works just like it does above -- use the UI to construct a query or dive right into the ADQL yourself.

Then in the remaining part of the screen, impose the constraints you want -- see the constraints section above.

At the bottom of the screen, you can "Populate and edit ADQL" if you want to work with the ADQL directly, or just search straight away after setting your search parameters.

This kind of search is somewhat hobbled in this tool; you may find it more satisfying to do this kind of search in the IRSA Viewer tool, specifically because this kind of search yields much more than just a row in a catalog; it can give you images, spectra, and more. This table is like any other table in this tool, so it can be sorted, filtered, etc.

VO SCS -- VO Simple Cone Search

To see this tab as a choice on the top, you may need to select it from the side menu.

As for the other searches, the tool may try to pre-fill the target position with the coordinates of the target with which you have been working. In this case, you are limited to a cone search, so the next option is the cone search radius. As usual, pick your units from the drop-down first, and then enter a number; if you enter a number and then select from the drop-down, it will convert your number from the old units to the new units. There are both upper and lower limits to your search radius; it will tell you if you request something too big or too small.

If you know your VO URL already, you can jump down to the Cone Search URL box and type or paste your URL into the box and hit search.

More commonly, however, users do not know a priori which URL to use. Click on "Find Astronomical Data Resources" to be dropped into a VO search. Find the URL corresponding to the catalog you want, copy it, and go back and paste it in the URL box. The URL should not have the RA and Dec in it; the tool will add your RA and Dec as listed to the URL in the right syntax. Click on "Search" to initiate the search.

Example

Load the tool. Search on IC1396. Go to the catalogs tab. Choose "VO Catalog." It wants the root URL for a cone search. Click on "Find Astronomical Data Resources", which goes here . Search on IPHAS. Get this page . Look for the complete catalog release (not just one associated with one specific study). The name of the catalog goes here . Hit the [+] to expand it. There is one URL listed there, under "available endpoints for the standard interface." Copy that URL and paste it into the search form. The IRSA tool will append your coordinates and radius and return you a table.

⚠ Tips and Troubleshooting

• Note that searching the VO means that you are using resources not specifically housed at IRSA, so servers may be down, or timeouts set, or limits on numbers of returned sources, etc., that are beyond our control. In most cases the solution is to specify as precise a search as possible. The URL you enter into the box in the search panel must be a Cone Search base URL (not containing RA and Dec parameters, which are inserted into the URL by the tool in response to the search parameters you give it).
• The master list of registries is here . You can also search the registries directly via that link (as opposed to via the IRSA tools).

The result of any VO SCS search is a catalog that can be interacted with like any other catalog in this tool.

NED Objects -- Searching for NED objects

NASA Extragalactic Database

To see this tab as a choice on the top, you may need to select it from the side menu.

As for the other catalog searches, the tool may pre-fill the target position with its best guess of the coordinates of the target with which you have been working. You can use an object name in place of coordinates. Note that although NED is used for name resolution, the actual search is then performed using coordinates, as opposed to name. In this case, you are limited to a cone search, so the next option is the cone search radius. Pick your units from the drop-down first, and then enter a number; if you enter a number and then select from the drop-down, it will convert your number from the old units to the new units. There are both upper and lower limits to your search radius; it will tell you if you request something too big or too small.

From the NED results, you have one-click access to the fully detailed information from NED on any object returned from such a search. The search results will generally include a column "Details", though you may have to scroll to the right to see it. Clicking on a link in this column takes you directly to the full NED information display for the selected object in a new window.

The result of any NED search is a table that behaves like any other table in this tool.