We report a detection of an absorption line at ~44.8 \AA in a > 500 ks
Chandra HRC-S/LETG X-ray grating spectrum of the blazar H 2356-309. This line
can be identified as intervening CV-K\alpha absorption, at z\approx0.112,
produced by a warm (logT = 5.1 K) intergalactic absorber. The feature is
significant at a 4.2\sigma level, with a 0.2% chance detection probability.
We estimate an equivalent hydrogen column density of log N_H=19.05 (Z/Zsun)^-1
cm^-2. Unlike other previously reported FUV/X-ray metal detections of warm-hot
intergalactic medium (WHIM), this CV absorber lies in a region with locally low
galaxy density, at ~2.2 Mpc from the closest galaxy at that redshift, and
therefore is unlikely to be associated with an extended galactic halo. We
instead tentatively identify this absorber with a genuine WHIM system
permeating a large-scale, 30 Mpc extended, filament of galaxies crossing the
sightline at z\approx0.112.
Description
[1202.5237] An X-ray WHIM metal absorber from a Mpc-scale empty region of space
%0 Generic
%1 Zappacosta2012
%A Zappacosta, Luca
%A Nicastro, Fabrizio
%A Krongold, Yair
%A Maiolino, Roberto
%D 2012
%K WHIM X-ray detection
%T An X-ray WHIM metal absorber from a Mpc-scale empty region of space
%U http://arxiv.org/abs/1202.5237
%X We report a detection of an absorption line at ~44.8 \AA in a > 500 ks
Chandra HRC-S/LETG X-ray grating spectrum of the blazar H 2356-309. This line
can be identified as intervening CV-K\alpha absorption, at z\approx0.112,
produced by a warm (logT = 5.1 K) intergalactic absorber. The feature is
significant at a 4.2\sigma level, with a 0.2% chance detection probability.
We estimate an equivalent hydrogen column density of log N_H=19.05 (Z/Zsun)^-1
cm^-2. Unlike other previously reported FUV/X-ray metal detections of warm-hot
intergalactic medium (WHIM), this CV absorber lies in a region with locally low
galaxy density, at ~2.2 Mpc from the closest galaxy at that redshift, and
therefore is unlikely to be associated with an extended galactic halo. We
instead tentatively identify this absorber with a genuine WHIM system
permeating a large-scale, 30 Mpc extended, filament of galaxies crossing the
sightline at z\approx0.112.
@misc{Zappacosta2012,
abstract = { We report a detection of an absorption line at ~44.8 {\AA} in a > 500 ks
Chandra HRC-S/LETG X-ray grating spectrum of the blazar H 2356-309. This line
can be identified as intervening CV-K{\alpha} absorption, at z\approx0.112,
produced by a warm (logT = 5.1 K) intergalactic absorber. The feature is
significant at a 4.2{\sigma} level, with a 0.2% chance detection probability.
We estimate an equivalent hydrogen column density of log N_H=19.05 (Z/Zsun)^-1
cm^-2. Unlike other previously reported FUV/X-ray metal detections of warm-hot
intergalactic medium (WHIM), this CV absorber lies in a region with locally low
galaxy density, at ~2.2 Mpc from the closest galaxy at that redshift, and
therefore is unlikely to be associated with an extended galactic halo. We
instead tentatively identify this absorber with a genuine WHIM system
permeating a large-scale, 30 Mpc extended, filament of galaxies crossing the
sightline at z\approx0.112.
},
added-at = {2012-02-24T17:08:20.000+0100},
author = {Zappacosta, Luca and Nicastro, Fabrizio and Krongold, Yair and Maiolino, Roberto},
biburl = {https://www.bibsonomy.org/bibtex/23769eefa24751b6b67bcd62472c56deb/miki},
description = {[1202.5237] An X-ray WHIM metal absorber from a Mpc-scale empty region of space},
interhash = {a2f70db18686c7e1b2363155273062ed},
intrahash = {3769eefa24751b6b67bcd62472c56deb},
keywords = {WHIM X-ray detection},
note = {cite arxiv:1202.5237Comment: submitted to ApJ, 6 pages, 4 figures, comments are welcome},
timestamp = {2012-02-24T17:08:20.000+0100},
title = {An X-ray WHIM metal absorber from a Mpc-scale empty region of space},
url = {http://arxiv.org/abs/1202.5237},
year = 2012
}