In this Letter we demonstrate that the two claims of $z0.03$ OVII
K$\alpha$ absorption lines from Warm Hot Intergalactic Medium (WHIM) along the
lines of sight to the blazars H~2356-309 (Buote et al., 2009; Fang et al.,
2010) and Mkn~501 (Ren, Fang & Buote, 2014) are likely misidentifications of
the $z=0$ OII K$\beta$ line produced by a diffuse Low-Ionization Metal Medium
in the Galaxy's Interstellar and Circum-Galactic mediums. We perform detailed
modeling of all the available high signal-to-noise Chandra LETG and XMM-Newton
RGS spectra of H 2356-309 and Mkn 501 and demonstrate that the $z0.03$
WHIM absorption along these two sightlines is statistically not required. Our
results, however, do not rule out a small contribution from the $z0.03$
OVII K$\alpha$ absorber along the line of sight to H~2356-309. In our model the
temperature of the putative $z = 0.031$ WHIM filament is T$= 310^5$ K
and the OVII column density is N$_OV II 410^15$ cm$^-2$,
twenty times smaller than the OVII column density previously reported, and now
more consistent with the expectations from cosmological hydrodynamical
simulations.
Description
[1602.03533] Diffuse Low-Ionization Gas in the Galactic Halo Casts Doubts on $z\simeq 0.03$ WHIM Detections
%0 Generic
%1 nicastro2016diffuse
%A Nicastro, F.
%A Senatore, F.
%A Gupta, A.
%A Mathur, S.
%A Krongold, Y.
%A Elvis, M.
%A Piro, L.
%D 2016
%K cgm galaxy ionisation low whim
%T Diffuse Low-Ionization Gas in the Galactic Halo Casts Doubts on $z\simeq
0.03$ WHIM Detections
%U http://arxiv.org/abs/1602.03533
%X In this Letter we demonstrate that the two claims of $z0.03$ OVII
K$\alpha$ absorption lines from Warm Hot Intergalactic Medium (WHIM) along the
lines of sight to the blazars H~2356-309 (Buote et al., 2009; Fang et al.,
2010) and Mkn~501 (Ren, Fang & Buote, 2014) are likely misidentifications of
the $z=0$ OII K$\beta$ line produced by a diffuse Low-Ionization Metal Medium
in the Galaxy's Interstellar and Circum-Galactic mediums. We perform detailed
modeling of all the available high signal-to-noise Chandra LETG and XMM-Newton
RGS spectra of H 2356-309 and Mkn 501 and demonstrate that the $z0.03$
WHIM absorption along these two sightlines is statistically not required. Our
results, however, do not rule out a small contribution from the $z0.03$
OVII K$\alpha$ absorber along the line of sight to H~2356-309. In our model the
temperature of the putative $z = 0.031$ WHIM filament is T$= 310^5$ K
and the OVII column density is N$_OV II 410^15$ cm$^-2$,
twenty times smaller than the OVII column density previously reported, and now
more consistent with the expectations from cosmological hydrodynamical
simulations.
@misc{nicastro2016diffuse,
abstract = {In this Letter we demonstrate that the two claims of $z\simeq 0.03$ OVII
K$\alpha$ absorption lines from Warm Hot Intergalactic Medium (WHIM) along the
lines of sight to the blazars H~2356-309 (Buote et al., 2009; Fang et al.,
2010) and Mkn~501 (Ren, Fang \& Buote, 2014) are likely misidentifications of
the $z=0$ OII K$\beta$ line produced by a diffuse Low-Ionization Metal Medium
in the Galaxy's Interstellar and Circum-Galactic mediums. We perform detailed
modeling of all the available high signal-to-noise Chandra LETG and XMM-Newton
RGS spectra of H 2356-309 and Mkn 501 and demonstrate that the $z\simeq 0.03$
WHIM absorption along these two sightlines is statistically not required. Our
results, however, do not rule out a small contribution from the $z\simeq 0.03$
OVII K$\alpha$ absorber along the line of sight to H~2356-309. In our model the
temperature of the putative $z = 0.031$ WHIM filament is T$= 3\times 10^5$ K
and the OVII column density is N$_{OV II} \le 4\times 10^{15}$ cm$^{-2}$,
twenty times smaller than the OVII column density previously reported, and now
more consistent with the expectations from cosmological hydrodynamical
simulations.},
added-at = {2016-02-12T10:25:58.000+0100},
author = {Nicastro, F. and Senatore, F. and Gupta, A. and Mathur, S. and Krongold, Y. and Elvis, M. and Piro, L.},
biburl = {https://www.bibsonomy.org/bibtex/2e8be49a09a8173e9f3b78dbe7b66a232/miki},
description = {[1602.03533] Diffuse Low-Ionization Gas in the Galactic Halo Casts Doubts on $z\simeq 0.03$ WHIM Detections},
interhash = {476c6853894f559079d17d709ca07750},
intrahash = {e8be49a09a8173e9f3b78dbe7b66a232},
keywords = {cgm galaxy ionisation low whim},
note = {cite arxiv:1602.03533Comment: 6 pages, 2 figures, accepted by MNRAS (Letter)},
timestamp = {2016-02-12T10:25:58.000+0100},
title = {Diffuse Low-Ionization Gas in the Galactic Halo Casts Doubts on $z\simeq
0.03$ WHIM Detections},
url = {http://arxiv.org/abs/1602.03533},
year = 2016
}