Chandra Spectral Atlas

Harvard-Smithsonian Center for Astrophysics

X-Atlas Logo

Note that additional spectral data are available from TGCat.

Catalog of Chandra Observations

  1. Target List
  2. Search X-Atlas Observations
  3. Hardness Ratios and Quantiles Listings
  4. Spectral Metric Listings
  5. Spectral Fit Listings
  6. Sample Spectral Montages
  7. Sample Line Profiles


  1. Navigating the X-Atlas Website (Threads)
  2. X-Atlas Abstract
  3. Data Processing
  4. Convolution to Low-Resolution
  5. Contact
  6. Please see: Owen W. Westbrook, Nancy Remage Evans, Scott J. Wolk, Vinay L. Kashyap, Joy S. Nichols, Peter J. Mendygral, Jonathan D. Slavin, and Wayne L. Waldron 2008, ApJS, 176, 218.

Other Catalogs

  1. Ultraviolet Hot Star Catalog
  2. Galactic O Star Catalog
  3. ANCHORS (AN archive of CHandra Observations of Regions of Star Formation)
  4. BiRD (XMM-Newton RGS Spectral Browsing Tool)
  5. IRTF Spectral Library
  6. TGCat (MIT Transmission Grating Catalog)
  7. SIMBAD: Search for your star

Related Sites

  1. Chandra X-ray Observatory Center
  2. Chandra Proposal Information
  3. XMEGA

X-ray Line Lists and Spectral Fitting

  1. Atomic Line List
  2. Chandra ATOMDB WebGUIDE
  3. NIST Spectral Line Lists
  4. WebSpec

About the X-Atlas Catalog

X-Atlas is a database of the X-ray spectra of over 250 observations made with the High Resolution Transmission Grating (HETG) on the Chandra X-ray Observatory. Originally intended as an atlas of the approximately 25 high-mass stars observed with HETG, X-Atlas has expanded to include not only low-mass stars but all point sources currently publicly available from the Chandra Data Archive, including novae, X-ray binaries, and active galactic nuclei. The atlas is intended to present an array of high-resolution spectral morphologies and line identifications for the rapid characterization and comparison of X-ray spectra. In addition, each high-resolution dataset has been convolved with the response of the ACIS detectors to match the low resolution of the ACIS image data, potentially allowing for further understanding and classification of sources observed by ACIS without the benefit of the gratings. For each target, the predicted low-resolution ACIS spectra are used to calculate hardness ratios and quantiles and to perform two-temperature spectral fits to extract temperatures, abundances, NH values, and fluxes. The atlas is accessible through this website, which offers interactive searching and plotting capabilities. The user can view the original HETG or predicted low-resolution observation with line identifications provided. Various spectral montages are offered as well.

Webpage last updated on Wednesday, 19-Jan-2011 15:44:06 EST by Brad Spitzbart (bspitzbart at