This chapter highlights the locations where FUSE data can be obtained
and also provides brief descriptions of available tools that can be
useful for analyzing and interpreting FUSE spectra. More information can be found on
CalFUSE Page. Lists of computer software, spectral atlases,
and papers dealing with particularly difficult FUSE analysis problems are also given.
The contents of this chapter are relevant to all future FUSE users regardless of their expertise level ("Casual", "Intermediate" or "Advanced").
FUSE data are available through three different on-line interfaces. These are:
Because FUSE data are standard FITS files, they can be read and displayed with all standard astronomical software packages. There are also several customized FUSE analysis packages written in IDL and in C that will assist the user in displaying and analyzing FUSE data. These tools, and their accompanying documentation, are available from the MAST or IAP web sites and are only briefly described here.
First, Don Lindler has written a comprehensive suite of IDL routines customized to handle FUSE data. These are called ltools. The complete package and some documentation are available from the MAST FUSE web pages. The following is an outline of the capabilities of ltools, and some of its major elements.
NOTE: Don Lindler's routines have been updated to work with IDL 6.3. If you are unable to display spectra when running fuse_register or cf_edit on a Mac or PC, try installing the latest versions of the astron and ltools libraries. Another trick is to add the following lines to your idl_startup.pro file.
; Let's deal with the 24-bit display issues. device, true_color=24 window, /free, /pixmap, colors=-10 wdelete, !d.window device, decomposed=0, retain=2, set_character_size=[8,10] device, get_visual_depth=depth ; Print helpful information at login. print, ' ' print, 'Display depth: ' + strtrim( depth, 2 ) print, 'Color table size: ' + strtrim( !d.table_size, 2 ) print, ' ' $pwd $hostname print, ' '
Some additional utility routines are:
Here are some additional contributions.
A final IDL tip to those users wishing to read FUSE data on their own: when using the IDL Astronomy User's Library routine mrdfits.pro, the keyword fscale should be set to automatically scale numbers to floating point format when needed.
FUSE Tools in C is a package of data analysis tools distributed along with the CalFUSE
pipeline. They come with the document
FUSE Tools in C, which
reviews each routine. A subset of these programs is designed specifically
for the manipulation of IDF files, and is described in the
Cookbook, which is available in both PDF and HTML versions on the FUSE
Tools web page
These tools have the flexibility to perform many common tasks, including
trimming, modifying and manipulating large sets of multiple data files. For
example, when combining spectra of bright targets, the goal is usually to
to maximize spectral resolution, so it is important to align the spectra
from individual exposures precisely before combining them. The
FUSE Tools in C package includes routines to accomplish this task.
In contrast, when
combining spectra of faint targets, the goal is typically to maximize the
fidelity of the background correction by increasing the signal-to-noise
ratio on unilluminated regions of the detector. To accomplish this, the
IDF files must be combined before extracting the spectra. This is easily
done with the Tools, and there are detailed instructions in the
Cookbook available on the
CalFUSE Page. The tools also have routines that enable
one to divide an IDF file into multiple time segments in order to examine
In a few cases, it may be necessary to reprocess the data using the CalFUSE pipeline. The CalFUSE source code and documentation for installing and using it are available at http:/archive.stsci.edu/fuse/analysis/calfuse.html.
Before performing detailed science investigations with FUSE data, it is recommended that the user (regardless of expertise level) go through the sanity checks given below to avoid erroneous results and interpretations.
There are a number of additional resources that are useful for analyzing FUSE data. These include line lists, spectral atlases, and a few other resources.
Don Morton has published an atlas of atomic data, complete with finding lists. These are available in the publication by Morton (2003). Because molecular hydrogen absorption is so prevalent in FUSE spectra, it is also important to be aware of the following references to the basic H2 data: Abgrall et al. (1993a) and Abgrall et al. (1993b). These are the data used by the McCandliss (2003) H2ools analysis package described above. The atomic data for interstellar Fe II lines (Howk et al. (2000)), interstellar Cl I lines (Sonnentrucker et al. (2006)), and stellar Fe II lines (Harper et al. (2001)) were also revised and should be considered for use in future studies.
Because a continuum source observed by FUSE with a color excess of only a few tenths will be littered with strong interstellar absorption lines, it is useful to have a rough idea of their expected strengths. Sembach (1999) provides lists of important interstellar features and detailed plots of synthetic interstellar spectra. The latter are especially useful for line identification purposes. The publications by McCandliss (2003) and Rachford et al. (2001) are also useful for their presentation of H2 spectra.
Table 8.1 lists the atlases of FUV spectra that were produced during the operational lifetime of the FUSE satellite. These atlases provide a useful introduction to the FUV spectra of a wide variety of Galactic and extragalactic objects. In many cases, the processed spectra can be downloaded for immediate inspection. Consequently, these atlases are valuable resources for many purposes, especially for researchers who are new to the FUV region of the spectrum.
|AG Dra (Symbiotic Star)||Young ||…|
|Cool Stars||Dupree ||…|
|Galactic OB Stars||Pellerin ||http://archive.stsci.edu/prepds/atlasfuse/|
|Magellanic OB Stars||Walborn ||http://archive.stsci.edu/prepds/atlasfuse/|
|Wolf-Rayet Stars||Willis ||http://archive.stsci.edu/prepds/fuse_wratlas/|
|Starburst Galaxies||Pellerin & Robert||http://archive.stsci.edu/prepds/fuse_galaxies/|
|Quasar Composite||Scott ||http://archive.stsci.edu/prepds/composite_quasar/|
Because FUSE spectra are always contaminated to some level by airglow, it is useful to be familiar with airglow spectra. Feldman et al. (2001) present an extensive set of airglow spectra observed with FUSE.
With the availability of a large body of IUE data already in the MAST archive, the FUSE project adopted an only slightly modified version of the IUE Object classes for use by FUSE. Table 8.2 lists the FUSE Object Classes.
Under class 99, Nulls & Flat Fields, the FUSE project has entered the following data types:
|Class - Object||Class - Object||Class - Object|
|0-Sun||31-A4-A9 V-IV||60-Shell Star|
|1-Earth||32-A0-A3 III-I||61-ETA Carinae|
|5-Minor Planet||36-AP||65-Misidentified Targets|
|7-Interplanetary Medium||38-HB Stars||69-Herbig-Haro Objects|
|8-Giant Red Spot||39-Composite Sp Type||70-PN + Central Star|
|10-W C||40-F0-F2||71-PN - Central Star|
|11-WN||41-F3-F9||72-H II Region|
|12-Main Sequence O||42-FP||73-Reflection Nebula|
|13-Supergiant O||43-Late-Type Degen||74-Dk Cld (Abs Spectrum)|
|14-OE||44-G V-IV||75-Supernova Remnant|
|15-OF||45-G III-I||76 Ring Neb (Shk Ionized)|
|16-SD O||46-K V-IV||80-Spiral Galaxy|
|17-WD O||47-K III-I||81-Elliptical Galaxy|
|19-Other Strong Sources||48-M V-IV||82-Irregular Galaxy|
|20-B0-B2 V-IV||49-M III-I||83-Globular Cluster|
|21-B3-B5 V-IV||50-R, N, or S Types||84-Seyfert Galaxy|
|22-B6-B9.5 V-IV||51-Long Period Var Stars||85-Quasar|
|23-B0-B2 III-I||52-Irregular Variables||86-Radio Galaxy|
|24-B3-B5 III-I||53-Regular Variables||87-BL Lacertae Object|
|25-B6-B9.5 III-I||54-Dwarf Novae||88-Em Line Gal(Non-Seyf)|
|26-BE 27-BP||55-Classical Novae||90-Intergalactic Medium|
|28-SDB||56-Supernovae||98-Wavelength Cal Lamp|
|29-WDB||58-T Tauri||99-Nulls & Flat Fields|