A Hubble Space Telescope/Cosmic Origins Spectrograph Search for Warm-hot Baryons in the Mrk 421 Sight Line

Details A Hubble Space Telescope/Cosmic Origins Spectrograph Search for Warm-hot Baryons in the Mrk 421 Sight Line A Hubble Space Telescope/Cosmic Origins Spectrograph Search for Warm-hot Baryons in the Mrk 421 Sight Line

Dec 2011

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2011apj...743...18d&link_type=abstract

The Astrophysical Journal, Volume 743, Issue 1, article id. 18 (2011).

Astronomy and Astrophysics

Astronomy

4

Bl Lacertae Objects: Individual: Mrk421, Cosmology: Observations, Intergalactic Medium, Quasars: Absorption Lines

Scientific paper

Thermally broadened Lyα absorbers (BLAs) offer an alternate method to using highly ionized metal absorbers (O VI, O VII, etc.) to probe the warm-hot intergalactic medium (WHIM, T = 105-107 K). Until now, WHIM surveys via BLAs have been no less ambiguous than those via far-UV and X-ray metal-ion probes. Detecting these weak, broad features requires background sources with a well-characterized far-UV continuum and data of very high quality. However, a recent Hubble Space Telescope/Cosmic Origins Spectrograph (COS) observation of the z = 0.03 blazar Mrk 421 allows us to perform a metal-independent search for WHIM gas with unprecedented precision. The data have high signal-to-noise ratio (S/N ≈ 50 per ~20 km s-1 resolution element) and the smooth, power-law blazar spectrum allows a fully parametric continuum model. We analyze the Mrk 421 sight line for BLA absorbers, particularly for counterparts to the proposed O VII WHIM systems reported by Nicastro et al. based on Chandra/Low Energy Transmission Grating observations. We derive the Lyα profiles predicted by the X-ray observations. The S/N of the COS data is high (S/N ≈ 25 pixel-1), but much higher S/N can be obtained by binning the data to widths characteristic of the expected BLA profiles. With this technique, we are sensitive to WHIM gas over a large (N H, T) parameter range in the Mrk 421 sight line. We rule out the claimed Nicastro et al. O VII detections at their nominal temperatures (T ~ 1-2 × 106 K) and metallicities (Z = 0.1 Z &sun;) at >~ 2σ level. However, WHIM gas at higher temperatures and/or higher metallicities is consistent with our COS non-detections.
Based on observations made with the NASA/ESA Hubble Space Telescope, obtained from the data archive at the Space Telescope Science Institute. STScI is operated by the Association of Universities for Research in Astronomy, Inc. under NASA contract NAS5-26555.

Affiliated with

Also associated with

No associations

Rating

A Hubble Space Telescope/Cosmic Origins Spectrograph Search for Warm-hot Baryons in the Mrk 421 Sight Line does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with A Hubble Space Telescope/Cosmic Origins Spectrograph Search for Warm-hot Baryons in the Mrk 421 Sight Line, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and A Hubble Space Telescope/Cosmic Origins Spectrograph Search for Warm-hot Baryons in the Mrk 421 Sight Line will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1892142