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The Spitzer Heritage Archive, or the SHA, is the final repository for all Spitzer data.
It is housed at the Infrared Science Archive, IRSA. When you first load the SHA, you are
dropped into a position search. You can type in a name and have either NED or SIMBAD resolve
the name, or you can type in coordinates in any of a variety of units and it will understand
what you mean. As you're typing, it echoes below the box what it thinks you've typed
so that you can make sure that it understood you correctly. The search radius, here, can
be entered in arcminutes, arcseconds, or degrees. Note that you need to put in the units before
you put in the number, because if you put in the number first, and then change the units,
it will convert the number that you've entered. Down here, an observation request, or an AOR,
an astronomical observation request, is the fundamental unit of Spitzer observing. I recommend
that when searching the SHA, you always leave this checked, because it is the most compact
way of displaying the search results in terms of observations. Level 2, or post-BCD products,
are the highest level products that come out of our automatic pipelines, such as mosaics
or extracted spectra. Level 1, or BCDs, are the individual data frames that are calibrated
that come out of our pipeline, and they go into making the post-BCD products. Over here,
you have a variety of enhanced products. The SSC Enhanced Products from the IRS team include
extracted spectra. The SEIP is the Spitzer Enhanced Imaging Products, and they include
Super Mosaics and a Source List. Contributed Enhanced Products are delivered from the community
back to IRSA for distribution. They are largely the Legacy teams, and largely include Spitzer
data, but they can also include data from other missions or surveys, depending on which
team delivered it back to us.
"More options" can be used to refine your search, such that you only get some of the
data products rather than whole AORs. You can search by instrument parameters or by
wavelength range. You can limit your search to just be IRAC, just be IRS, or just MIPS,
or just modes of them. You can limit your search by frame time or date of observation.
For this example, we're just going to search.
It's come back with one tab for each one of the boxes that we checked. Up here, it gives
us a summary of the search that we did. If you want to go back and repeat the search,
or change it, you can click on the searches tab, and it will drop you back into a position
search. The History tab gives you access to the history of your searches during this session.
You can also load in a FITS file from disk, set your preferences, get access to help,
or load catalogs, or search catalogs. Up here, you can log in. You don't have to log in,
but you can, and this way you can save your preferences and your searches, and get access
to proprietary if you're authorized.
The AOR tab here, as promised, is the most compact way of displaying the observations.
The red rows are still proprietary data and are not yet publicly available. All the rest
of the observations shown here are publicly available. The target name was entered by
the original observer. The right ascension and declination are given here. If it's a
moving target, it has a NAIF ID here. There's the instrument and mode that was used here,
and the AORKEY, which is the unique, large integer number that uniquely identifies the
observation within the Spitzer mission. The AOR Label was provided by the original observer.
Here's the observation start time and end time. Here's the program ID that refers to
the program that includes that AOR, and the PI of that observation.
For each one of the rows in the results pane, like window pane here, you can see the stuff
on the right hand side changes. By clicking on each row, you can get details about the
original program, and that specific observation. The AOR DoC image gives you a depth of coverage
image, where the shades of grey correspond to individual frames obtained. The catalog
that's overlaid is something we'll get to in a minute. The AOR footprint here gives
you a footprint of the individual observation that you've selected on a background image,
in this case, an IRAS image. If you pick a different observation, it will give you a
different footprint.
The Level 2 Post-BCD tab gives you the highest level data products provided by our pipelines,
such as extracted spectra or mosaics. The Level 1 BCD tab gives you the individual frames
that went into each of the observations. Note that, currently, we have 16,697 individual
frames here for an original 42 observations. If you want to limit exactly what you see
in the Level 2 or Level 1 tabs, make sure that "Restrict data in other tabs" is checked,
click on the row corresponding to the observation you're interested in, and check the box. Now,
when you go to the Level 2 Post-BCD tab, you see only the frames associated with that observation,
and the same for the Level 1 BCDs, you see only the frames that went into that observation.
From the AOR level, you can also filter it down so that you only see one kind of observation.
You can, for example, click on the filter icon and say, I just want to see the IRAC
Map observations, or, I just want to see the MIPS SED observations. To cancel the filters,
click on cancel. You can also implement filters by typing in things in the box to restrict
what is shown. The IRS Enhanced tab shows you the spectra that it found consistent with
your search. Here, it's found one spectrum, and you can see it in the data tab over here.
You can interact with the spectrum in this way. In the Super Mosaics tab, it found 18
mosaics consistent with our search. Some of them are long mosaics; some of them are short
mosaics. If you click on them, in the data tab, it will give you the real image here.
In this case, it's difficult to see, because of the source list that is overlaid. To remove
this, go to the image toolbox, click on plot layers, and remove the overlay. Now you can
see the original data frame underneath, complete with M101, which was our search target.
The source list tab is the entire source list that it retrieved consistent with our search.
Let's put them back over the image, and you can see the catalog is overlaid here. If you
click on individual sources in the image, that source is highlighted in the catalog,
and it works the other way as well. For contributed products, it gives you a list of all the things
that it found -- it found images from three different Legacy teams: LVL, SINGS, and S4G.
It found catalogs from S4G. To learn more about these individual projects and what,
exactly, they delivered, click on the more link to be taken to additional pages that
give you more information about those projects.
For the catalog, click on column definition that defines the columns that are present
in the catalog. To load them into the SHA, click on the name of the project, and it will
load a list of images, in this case, that it found from LVL. Note that it's giving you
all of the things that LVL delivered that are consistent with our search, including
data that are not from Spitzer -- in this case, there is GALEX data. To make it go away,
click on the x.
To download data, from the AOR tab, you can check the box at the top to select all of
the available data here, or you can select individual AORs. And, then click "prepare
download" to package up all the data associated with those AORs. You can tell it exactly what
you want; you can give it email, and it will send you email when it's done packaging.
You can also do this from the Level 2 tabs, or the Level 1 tabs. The other tabs work similarly,
but they are not linked back to the original AORs. You can click Super Mosaics and download
all of them. You can click Source List; you can save the table that way, or select individual
sources. In order to download contributed products, you must load them into a tab, and
then save them.
From the AOR level, for example, I've selected those 3 AORs. Click "prepare download", it
will spin it off to the background monitor, and let you know when it's ready. You can
click the link to watch it package. If it gives you many different packages, it will
give you an option to download a wget script that will enable you to automatically download
those zip files to your disk.
If it's taking a long time to package, and you wish that you had entered an email, you
can enter an email here, and it will email you when it's done.
There are many other ways to search the Spitzer Heritage Archive. If you go over here, you
can search all of the abstract text. For example, you can search on all projects that set out
to observe planetary nebulae, or brown dwarfs. It will then search all the abstracts of all
of the programs, and give you a list of everything. To load those AORs corresponding to one of
those programs, click on the title, and it will give you all the AORs associated with
that program.
Additional search options include searching by AORKEY, which is the large integer that
uniquely identifies the observation in the Spitzer Heritage Archive. AORKEYs should be
published in papers using Spitzer data so that you can go back and retrieve the AOR
that was used. You can search by campaign. You can search the IRS enhanced products over
the whole sky. You can search for moving objects. You can look for objects that were either
serendipitously or deliberately observed during the Spitzer mission. Caution, though -- if
you search the whole 10 years of the mission at once, it will take a long time to complete.
You can search by observation date. You can search by observer. Or, you can search by
program.
Let's go back to our original search from before. We can go to history, and resubmit
the search that we did before. For this example, let's limit this so that I just have IRAC
images in the Post-BCD tab. Now, if I look in the Data tab, I'm interacting with the
actual data here. There's actually lots of sophisticated tools for working with the FITS
image. By clicking on the image toolbox, I bring up a toolbox. I can also make the image
big. I can zoom in. I can zoom out. I can zoom to the original size. I can make it as
big as possible to fit in the available space. I can fill the available space. I can return
everything to the defaults. I can change the color table. I can change the color stretch.
I can customize the image stretch to something I specifically want for this image. I can
get access to the FITS header, and I can sort the keywords so I can find a specific keyword
in which I'm interested. I can overlay a grid on the image. I can crop the image, or I can
select a region for getting statistics. I can rotate the image to any arbitrary angle.
I can rotate it so North is up. I can flip the image on the y axis. I can measure distances
on the image by selecting that, and then clicking and dragging. To actually see the measurement,
go to the plot layers, and it will show the distance tool here, in units of degrees here.
It also has the option to give me the offset calculation in degrees north and east. I can
show the center of the query. I can import a ds9 regions file to overlay on the image.
I can add a compass rose showing where North is up. I can recenter the image on the last
query or the center of the image. Or, I can access the plot layers. There is context-sensitive
help throughout the SHA. Let your mouse hover, click on the blue question marks to bring
up help corresponding to what you're looking at.
You can also overlay catalogs. If you click on the catalogs tab, you're dropped by default
into a catalog search. You can also load catalogs from disk. Let's search the catalogs. It remembers
the target we searched on before. We can do a cone search. We must pick a project first
to search on. It comes up with 2MASS by default. But you can pick anything from a variety of
missions. Let's get the WISE catalog over a relatively small area. So, here's the WISE
catalog. You can also make plots from the catalog. Over here, you have the table icon
selected -- let's click on the plot icon. It will then change the table into a plot
form. By default, it comes up plotting RA and Dec; you can change what is plotted by
clicking on the gears. In this case, it is a WISE catalog, so it has a wide variety of
columns. You can click on the 'cols' link to select any of the individual columns that
appear in the catalog. In this case, I happen to know what the names of the columns are.
So, let's plot w1mpro-w4mpro. And, for the y-axis, let's plot w1mpro. Let's apply. There,
it makes a plot of all the sources that it retrieved. Note that it's plotted it strictly
mathematically correctly such that big numbers are at the top. In order to make this plot
more like what I'm expecting, I can plot -w1mpro. Apply. I can do simple mathematical manipulations
here too - logarithms, that sort of thing, and plot exactly what I want. I can control
what the labels and the units are as shown. I can change exactly what is plotted by typing
in the minimum and maximum. I can also click and drag to select a region. If I filter down
so that the catalog as shown consists just of those sources, if I click on individual
sources and go back to table view, that source is the one that's highlighted. Note that I
have only 660 source shown here now; that's because we did that filtering and that zooming
to get down to that level. To return to the original view, click reset, and it goes back
to the right ascension and declination. To make the plot bit, click on the arrows. Note
that it has two images currently loaded in, so it's giving you the FITS image here, and
the plot here. To view just one, click on the single view icon, and scroll through to
find the xy plot.