J/ApJ/921/134 DES DR1 galaxies in the field of FRB 180924 (Simha+, 2021)
Estimating the contribution of foreground halos to the FRB 180924 dispersion
measure.
Simha S., Tejos N., Prochaska J.X., Lee K.-G., Ryder S.D., Cantalupo S.,
Bannister K.W., Bhandari S., Shannon R.M.
<Astrophys. J., 921, 134 (2021)>
=2021ApJ...921..134S 2021ApJ...921..134S
ADC_Keywords: Galaxies; Photometry, ugriz; Spectra, optical; Redshifts; Surveys;
Radio sources; Transient
Keywords: Galaxy dark matter halos ; Cosmology ;
Quasar absorption line spectroscopy ; Radio transient sources ;
Extragalactic astronomy
Abstract:
Fast radio burst (FRB) dispersion measures (DMs) record the presence
of ionized baryons that are otherwise invisible to other techniques
enabling resolution of the matter distribution in the cosmic web. In
this work, we aim to estimate the contribution to FRB 180924 DM from
foreground galactic halos. Localized by ASKAP to a massive galaxy,
this sightline is notable for an estimated cosmic web contribution to
the DM (DMcosmic=220pc/cm3), which is less than the average value
at the host redshift (z=0.3216) estimated from the Macquart relation
(280pc/cm3). In the favored models of the cosmic web, this suggests
few intersections with foreground halos at small impact parameters
(≤100kpc). To test this hypothesis, we carried out spectroscopic
observations of the field galaxies within ∼1' of the sightline with
VLT/MUSE and Keck/LRIS. Furthermore, we developed a probabilistic
methodology that leverages photometric redshifts derived from
wide-field DES and WISE imaging. We conclude that there is no galactic
halo that closely intersects the sightline and also that the net DM
contribution from halos DMhalos<45pc/cm3 (95% c.l.). This value is
lower than the DMhalos estimated from an "average" sightline
(121pc/cm3) using the Planck ΛCDM model and the Aemulus halo
mass function and reasonably explains its low DMcosmic value. We
conclude that FRB 180924 represents the predicted majority of
sightlines in the universe with no proximate foreground galactic
halos. Our framework lays the foundation for a comprehensive analysis
of FRB fields in the near future.
Description:
We obtained photometric data in the grizY bands for all sources within
15' of FRB 180924 from DES DR1 (Abbott+ 2018, II/357 ; 95% complete to
r=23.35). This was supplemented with photometry from the Wide-field
Infrared Survey Explorer (WISE; Wright+ 2010AJ....140.1868W 2010AJ....140.1868W) database
where available. See Section 2.1.
For the galaxies at 0.001<z<0.05 along the sightline, we turned to
the 2MASS survey database (Huchra+ 2012, J/ApJS/199/26) for
spectroscopic data. This catalog contains galaxy spectra of 83% of the
southern sky and is complete to J<13.75 with median redshift z=0.053.
To survey galaxies close to the FRB sightline we used the MUSE
integral field unit on the Very Large Telescope (VLT). A set of 4x628s
exposures were obtained on UT 2018 November 5 from program 2102.A-5005
(PI Macquart); another set of 4x600s exposures were obtained on UT
2019 December 6 from program 0104.A-0411 (PI Tejos). These
observations were carried out in the Wide-Field Adaptive Optics mode,
corresponding to an effective FoV of 1'x1' with a pixelscale of 0.2",
and covering a wavelength range of R∼4800-9300Å at a resolving
power of ∼2000-4000, respectively.
We also obtained spectra of five galaxies using the Low Resolution
Imaging Spectrograph (LRIS) installed on the Keck telescope on
2020-November-8 in the longslit spectroscopy mode.
See Section 2.2.
Objects:
----------------------------------------------------------
RA (ICRS) DE Designation(s)
----------------------------------------------------------
21 44 25.25 -40 54 00.1 FRB 180924 = FRB 20180924B
----------------------------------------------------------
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 88 11219 Catalog of photometry from DES and WISE for galaxies
in the FRB 180924 field
table2.dat 54 20 MUSE and LRIS sources with unambiguous redshifts
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See also:
II/328 : AllWISE Data Release (Cutri+ 2013)
II/357 : The Dark Energy Survey (DES): Data Release 1 (Abbott+, 2018)
II/371 : The Dark Energy Survey (DES): Data Release 2 (Abbott+, 2021)
I/355 : Gaia DR3 Part 1. Main source (Gaia Collaboration, 2022)
J/ApJ/740/91 : Lyα and OVI in galaxies around quasars (Prochaska+, 2011)
J/ApJS/199/26 : The 2MASS Redshift Survey (2MRS) (Huchra+, 2012)
J/AJ/145/101 : Updated nearby galaxy catalog (Karachentsev+, 2013)
J/other/PASA/33.45 : FRBCAT: The Fast Radio Burst (FRB) Cat. (Petroff+, 2016)
J/ApJ/901/134 : Foreground galaxies toward FRB 190608 from SDSS (Simha+, 2020)
J/ApJS/257/59 : First CHIME/FRB Fast Radio Burst Cat. (CHIME/FRB Col.+, 2021)
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 9 I9 --- CoadID DES DR1 main COADDOBJECTID value
( in Simbad)
11- 19 F9.5 deg RAdeg [325.77/326.44] Right Ascension (J2000)
21- 29 F9.5 deg DEdeg [-41.15/-40.65] Declination (J2000)
31- 35 F5.2 mag gmag [13.95/]?=99 DES apparent g band AB magnitude
37- 41 F5.2 mag rmag [17/]?=99 DES apparent r band AB magnitude
43- 47 F5.2 mag imag [15.78/28.8] DES apparent i band AB magnitude
49- 53 F5.2 mag zmag [14.29/29] DES apparent z band AB magnitude
55- 59 F5.2 mag Ymag [13.3/]?=99 DES apparent Y band magnitude
61- 65 F5.2 mag W1mag [11.39/17.74]? WISE W1 (3.36um) band Vega magnitude
67- 71 F5.2 mag W2mag [11.45/17.34]? WISE W2 (4.62um) band Vega magnitude
73- 77 F5.2 mag W3mag [9.9/12.55]? WISE W3 (12.1um) band Vega magnitude
79- 82 F4.2 mag W4mag [7/9.1]? WISE W4 (22.2um) band Vega magnitude
84- 88 F5.3 --- z [0.034/5.9] Photometric redshift
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Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 9 F9.5 deg RAdeg Right ascension in decimal degrees (J2000)
11- 19 F9.5 deg DEdeg Declination in decimal degrees (J2000)
21 A1 --- f_zsp Note on zsp (1)
23- 29 F7.5 --- zsp [0.072/2.96] Unambiguous spectroscopic redshift
31- 39 I9 --- CoadID [209914131/209916475]? DES DR1 CoadID (2)
41- 45 F5.2 mag rmag [18.69/24.54]? r-band AB magnitude
47- 50 F4.2 arcmin Sep [0.01/1.98] Angular separation from the FRB
52- 54 I3 kpc Dist [3/252] Angular separation converted to
projected distance from the FRB sightline
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Note (1): Flag as follows:
d = Host galaxy
e = LRIS spectrum
Note (2): Ellipses imply objects are not present in the DES database.
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 24-Feb-2023