Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The Dearth of Chemically Enriched Warm-Hot Circumgalactic Gas   The circumgalactic medium (CGM) around galaxies is believed to record various
forms of galaxy feedback and contain a significant portion of the "missing
baryons" of individual dark matter halos. However, clear observational evidence
for the existence of the hot CGM is still absent. We use intervening galaxies
along 12 background AGNs as tracers to search for X-ray absorption lines
produced in the corresponding CGM. Stacking Chandra grating observations with
respect to galaxy groups and different luminosities of these intervening
galaxies, we obtain spectra with signal-to-noise ratios of 46-72 per 20-mA
spectral bin at the expected OVII Kalpha line. We find no detectable absorption
lines of CVI, NVII, OVII, OVIII, or NeIX. The high spectral quality allows us
to tightly constrain upper limits to the corresponding ionic column densities
(in particular log[N(OVII)(cm^{-2})]<=14.2--14.8). These nondetections are
inconsistent with the Local Group hypothesis of the X-ray absorption lines at
z~0 commonly observed in the spectra of AGNs. These results indicate that the
putative CGM in the temperature range of 10^{5.5}-10^{6.3} K may not be able to
account for the missing baryons unless the metallicity is less than 10% solar.

35
The categories of this paper are: mtrl-th
28
The categories of this paper are: alg-geom
29
The categories of this paper are: funct-an
21
The categories of this paper are: adap-org
33
The categories of this paper are: plasm-ph
32
The categories of this paper are: atom-ph
11
The categories of this paper are: hep-lat
9
The categories of this paper are: nlin
14
The categories of this paper are: math-ph
23
The categories of this paper are: solv-int
24
The categories of this paper are: dg-ga
15
The categories of this paper are: nucl-ex
7
The categories of this paper are: hep-th
27
The categories of this paper are: comp-gas
2
The categories of this paper are: math
37
The categories of this paper are: supr-con