Quick Guide to HEASARC - Ann Hornschemeier
A quick guide to getting started on HEASARC
Ann E. Hornschemeier
(All information based on the user's guide
distributed by the High Energy Astrophysics
Science Archive Research Center, October 24,1994)
Where to find HEASARC:
1. http://heasarc.gsfc.nasa.gov/
2.
a. telnet heasarc.gsfc.nasa.gov
b. log in as "xray"
c. give your HEASARC username (or invent one)
d. The first time, you will be prompted for your email
address and postal address.
**NOTE: Give the email address that you will be using the
most often. In the future, if you log in from a
different address, type "email" at the HEASARC
prompt and change the address. This avoids a lot
of confusion.
Where to find help:
1. Email request@legacy.gsfc.nasa.gov
2. help command_name
3. command ? <- This is for instances that a command has options and
you can't remember your options. It will list some
options. Type 'exit' when it asks a second time if
you do not want to perform this command.
How to begin a session in BROWSE:
browse database_name
Good, vague, starting data bases:
ALLDATA - 3 guesses...
XRAY - X-ray Catalogs
RADIO - Radio Catalogs
OBSLOG - Observation Logs
OPTICAL - Optical Catalogs
The prompts:
HEASARC> -You're _not_ in BROWSE, most commands here
are BROWSE commands.
DATABASE_SAMPLE_PARM> -You're in BROWSE. This lists the present
data base, the present sample, and the present
search parameter (default is declination).
Aliases:
1. To make an alias:
> alias name command_string
2. To list out aliases:
> alias/show
Searching a data base:
1. To get a listing of possible search parameters, type lparm for
"list parameters" :
2. Searching by name:
There is an alias "sname" for this purpose:
>sn 3c39* -wildcards will work
-Note: Everything found when searching by
parameter will be displayed, so limit your
search as much as possible.
3. Searching by coordinates:
>sc -This is "search in a cone." RA and Dec are
given in h min sec and deg min sec, respectively.
An outer an inner radius can be selected if you want
a "hollow" cone search.
4. Searching by another parameter:
>sp PARM low high
>sp LII 0.0 2.0 -Searches the present sample for objects
between 0 and 2 degrees galactic latitude.
Sorting data:
>sort/ascending PARM
>sort/descending PARM
Filtering data:
>sef ? -This lists out all possible filtering parameters.
>sef PARM low high -Exclusive filter
>sef PARM low high -Inclusive filter
Displaying your findings:
>dsam -displays everything in your sample
>dsam 1-10 20-30 -displays only entries 1-10 and 20-30
Plotting an image:
1. Set the plotting device. This is done with "cpd", change
plot device. i.e. cpd /xterm
2. ximage/im 1
Plots the FITS image of the first item in the present
sample.. The default is contour, add /nocontour otherwise.
Making a plot by parameter:
>ps/plt PARM1 PARM2 -plots PARM1 versus PARM2
>ps/aitoff -makes an equal area projection
Histograms
There's an alias, phisto, for "ps/histo":
>phisto PARM -makes a histogram of PARM for given sample
>phisto/bins=100 PARM -default is 30 bins, this can be adjusted
Extracting files:
1. Type "lfiles" to find out if there's anything to extract.
2. If there are files to be extracted, figure out what you want.
You can get anything from FITS images to photon counts. The
available files for a data base are listed in the _Available
Databases_ guide.
3. Type xp/all to get all files.
Basic spectral analysis:
>xspec/int 1 -Run xspec in an interactive mode, using
the first item in the present sample.
>model ? -This will list both the additive and
multiplicative models. You must specify
at least one additive model and as many
multiplicative models as you like.
>fit -make the fit
>plot model -plots the best fit
Sending files:
1. "exit" to get out of BROWSE then type:
HEASARC> send filename
2. This sets up an ftp connection for you, wild cards will work.
A short list of possible data sources:
Einline
This page at http://hea-www.harvard.edu/einline/einline.html
gives access to Einline, the data archive of the Einstein mission.
If you telnet to einline.harvard.edu, log in as "einline" and you
will be connected to this service directly.
Files can be obtained through anonymous ftp to einline.harvard.edu
Leicester Database and Archive Center
This database can be found at http://ledas-www.star.le.ac.uk/
It covers ROSAT and GINGA.
NASA Astrophysics Data System Home Page
The ADS can be reached at http://adscat.harvard.edu/
It contains abstract and article searches (which eventually will
include ApJ back to 1975), a data archive, and a catalog service.
Astronomical Data Center Home Page (Goddard)
Through this page, HEASARC and other services can be accessed.
The address is http://nssdc.gsfc.nasa.gov/adc/adc.html
If you telnet to nssdc.gsfc.nasa.gov, log in as NODIS and you will
be connected directly to the NSSDC Online Data and Information Center.
Files can then be obtained through anonymous ftp to nssdc.gsfc.nasa.gov
Astronomy and Astrophysics Abstracts
Table 13 in the D.H. Hill reference section and QB460.A87 in the stacks.
An object index is included, with listings by nearly every naming
convention known to the universe as we know it.
Ann's home page.
Back to the resources page.