|
| | | | |
| | | |
| Stat |
Members: 3645
Articles: 2'500'096
Articles rated: 2609
18 April 2024 |
|
| | | | |
|
Article overview
| |
|
|
Galaxy gas as obscurer: I. GRBs x-ray galaxies and find a N_H ~ M* relation | | Johannes Buchner
; Steve Schulze
; Franz E. Bauer
; | | Date: |
28 Oct 2016 | | Abstract: | An important constraint for galaxy evolution models is how much gas resides
in galaxies, in particular at the peak of star formation z=1-3. We attempt a
novel approach by letting long-duration Gamma Ray Bursts (LGRBs) x-ray their
host galaxies and deliver column densities to us. This requires a good
understanding of the obscurer and biases introduced by incomplete follow-up
observations. We analyse the X-ray afterglow of all 844 Swift LGRBs to date for
their column density $N_H$. To derive the population properties we propagate
all uncertainties in a consistent Bayesian methodology. The $N_H$ distribution
covers the $10^{20-23}mathrm{cm}^{-2}$ range and shows no evolutionary effect.
Higher obscurations, e.g. Compton-thick columns, could have been detected but
are not observed. The $N_H$ distribution is consistent with sources randomly
populating a ellipsoidal gas cloud of major axis
$N_H^ ext{major}=10^{23}mathrm{cm}^{-2}$ with 0.22 dex intrinsic scatter
between objects. The unbiased SHOALS survey of afterglows and hosts allows us
to constrain the relation between Spitzer-derived stellar masses and X-ray
derived column densities $N_H$. We find a well-constrained powerlaw relation of
$N_H=10^{21.7}mathrm{cm}^{-2} imesleft(M_{star}/10^{9.5}M_{odot}
ight)^{1/3}$,
with 0.5 dex intrinsic scatter between objects. The Milky Way and the
Magellanic clouds also follow this relation. From the geometry of the obscurer,
its stellar mass dependence and comparison with local galaxies we conclude that
LGRBs are primarily obscured by galaxy-scale gas. Ray tracing of simulated
Illustris galaxies reveals a relation of the same normalisation, but a steeper
stellar-mass dependence and mild redshift evolution. Our new approach provides
valuable insight into the gas residing in high-redshift galaxies. | | Source: | arXiv, 1610.9379 | | Services: | Forum | Review | PDF | Favorites | |
|
|
No review found.
Did you like this article?
Note: answers to reviews or questions about the article must be posted in the forum section.
Authors are not allowed to review their own article. They can use the forum section.
browser claudebot
|
| |
|
|
|
|
News, job offers and information for researchers and scientists:
| |
REGISTER