J/ApJ/901/134 Foreground galaxies toward FRB 190608 from SDSS (Simha+, 2020)
Disentangling the Cosmic Web toward FRB 190608.
Simha S., Burchett J.N., Prochaska J.X., Chittidi J.S., Elek O.,
Tejos N., Jorgenson R., Bannister K.W., Bhandari S., Day C.K., Deller A.T.,
Forbes A.G., Macquart J.-P., Ryder S.D., Shannon R.M.
<Astrophys. J., 901, 134 (2020)>
=2020ApJ...901..134S 2020ApJ...901..134S
ADC_Keywords: Galaxies, spectra; Redshifts; Photometry, SDSS; Optical;
Intergalactic medium
Keywords: Galaxy dark matter halos ; Quasar absorption line spectroscopy ;
Galaxy evolution ; Intergalactic medium ; Radio transient sources
Abstract:
Fast radio burst (FRB) 190608 was detected by the Australian Square
Kilometre Array Pathfinder (ASKAP) and localized to a spiral galaxy at
zhost=0.11778 in the Sloan Digital Sky Survey (SDSS) footprint. The
burst has a large dispersion measure (DMFRB=339.8pc/cm3) compared
to the expected cosmic average at its redshift. It also has a large
rotation measure (RMFRB=353rad/m2) and scattering timescale
(τ=3.3ms at 1.28GHz). Chittidi+ (2021ApJ...922..173C 2021ApJ...922..173C) perform a
detailed analysis of the ultraviolet and optical emission of the host
galaxy and estimate the host DM contribution to be 110±37pc/cm3.
This work complements theirs and reports the analysis of the optical
data of galaxies in the foreground of FRB 190608 in order to explore
their contributions to the FRB signal. Together, the two studies
delineate an observationally driven, end-to-end study of matter
distribution along an FRB sightline, the first study of its kind.
Combining our Keck Cosmic Web Imager (KCWI) observations and public
SDSS data, we estimate the expected cosmic dispersion measure
DM_cosmic along the sightline to FRB 190608. We first estimate the
contribution of hot, ionized gas in intervening virialized halos
(DMhalos∼7-28pc/cm3). Then, using the Monte Carlo Physarum Machine
methodology, we produce a 3D map of ionized gas in cosmic web
filaments and compute the DM contribution from matter outside halos
(DMIGM∼91-126pc/cm3). This implies that a greater fraction of
ionized gas along this sightline is extant outside virialized halos.
We also investigate whether the intervening halos can account for the
large FRB rotation measure and pulse width and conclude that it is
implausible. Both the pulse broadening and the large Faraday rotation
likely arise from the progenitor environment or the host galaxy.
Description:
FRB 190608 was detected and localized by the Australian Square
Kilometre Array Pathfinder (ASKAP) to
RAJ2000=22:16:4.77,DEJ2000=-07:53:53.7 (Day+ 2020MNRAS.497.3335D 2020MNRAS.497.3335D),
placing it in the outer disk of the galaxy J221604.90-075356.0 at
z=0.11778 cataloged by the Sloan Digital Sky Survey (SDSS).
To search for nearby foreground galaxies, we obtained six 33"x20"
integral field unit (IFU) exposures (1800s each) using the Keck Cosmic
Web Imager (KCWI) in a mosaic centered at the host galaxy centroid
(R∼900). The six exposures cover an approximately 1'x1' field around
the FRB host. To summarize, we found no foreground galaxy in the 1'2
KCWI field. See Section 2.
To expand the sample, we then queried the SDSS-DR16 database for all
spectroscopically confirmed galaxies with impact parameters b<5Mpc
(physical units) to the FRB sightline and z<zhost.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 73 203 Observed and derived properties of the spectroscopic
foreground galaxies from SDSS
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See also:
V/154 : Sloan Digital Sky Surveys (SDSS), Release 16 (DR16) (Ahumada+, 2020)
J/ApJ/773/92 : XMM survey of soft background. III. Gal. halo (Henley+, 2013)
J/ApJ/785/104 : redMaPPer. I. Algorithm applied to SDSS DR8 (Rykoff+, 2014)
J/other/PASA/33.45 : FRBCAT: The Fast Radio Burst (FRB) Cat. (Petroff+, 2016)
http://www.sdss.org/dr16/ : SDSS DR16 home page
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 9 F9.5 deg RAdeg [330.84/340.4] Right Ascension (J2000)
11- 18 F8.5 deg DEdeg [-9.73/1.4] Declination (J2000)
20- 24 F5.2 mag umag [16.02/26.54] SDSS u band magnitude
26- 30 F5.2 mag gmag [14.39/22.21] SDSS g band magnitude
32- 36 F5.2 mag rmag [13.69/21.71] SDSS r band magnitude
38- 42 F5.2 mag imag [13.34/24.36] SDSS i band magnitude
44- 48 F5.2 mag zmag [13.11/22.83] SDSS z band magnitude
50- 56 F7.5 --- z [0.005/0.12] Spectroscopic redshift
58- 61 I4 kpc b [158/4983] Impact parameter
63- 67 F5.2 [Msun] logM* [5.34/11.17] log stellar mass
69- 73 F5.2 [Msun] logMhalo [9.45/13.49] log halo mass
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 14-Jan-2022