J/MNRAS/493/5336 Circumgalactic medium of galaxies at z∼4-5 (Bielby+, 2020)
Into the Ly α jungle: exploring the circumgalactic medium of galaxies at
z∼4-5 with MUSE.
Bielby R.M., Fumagalli M., Fossati M., Rafelski M., Oppenheimer B.,
Cantalupo S., Christensen L., Fynbo J.P.U., Lopez S., Morris S.L.,
D'Odorico V., Peroux C.
<Mon. Not. R. Astron. Soc., 493, 5336-5356 (2020)>
=2020MNRAS.493.5336B 2020MNRAS.493.5336B (SIMBAD/NED BibCode)
ADC_Keywords: Galaxies ; Galaxies, group ; Galaxies, spectra ; QSOs ;
Redshifts ; Ultraviolet ; Optical
Keywords: galaxies: evolution - galaxies: groups: general -
galaxies: high-redshift - intergalactic medium
Abstract:
We present a study of the galaxy environment of nine strong HI+CIV
absorption line systems (16.2<log(N(HI))<21.2) spanning a wide range
in metallicity at z∼4-5, using MUSE integral field and X-Shooter
spectroscopic data collected in a z∼5.26 quasar field. We identify
galaxies within a 250kpc and ±1000km/s window for six out of the
nine absorption systems, with two of the absorption line systems
showing multiple associated galaxies within the MUSE field of view.
The space density of Lyα emitting galaxies (LAEs) around the HI
and CIV systems is ∼10-20 times the average sky density of LAEs given
the flux limit of our survey, showing a clear correlation between the
absorption and galaxy populations. Further, we find that the strongest
CIV systems in our sample are those that are most closely aligned with
galaxies in velocity space, i.e. within velocities of ±500km/s. The
two most metal-poor systems lie in the most dense galaxy environments,
implying we are potentially tracing gas that is infalling for the
first time into star-forming groups at high redshift. Finally, we
detect an extended Lyα nebula around the z∼5.26 quasar, which
extends up to ∼50kpc at the surface brightness limit of
3.8x10-18erg/s/cm2/arcsec2. After scaling for surface brightness
dimming, we find that this nebula is centrally brighter, having a
steeper radial profile than the average for nebulae studied at z∼3 and
is consistent with the mild redshift evolution seen from z∼2.
Description:
MUSE observations in the quasar field SDSS J074749.17+115352.4 have
been collected as part of ESO programme 0102.A-0261 (PI: Bielby)
between 2018 December and 2019 March, using the Wide Field Mode
combined with the GALACSI (Ground Atmospheric Layer Adaptive Corrector
for Spectroscopic Imaging) adaptive optics system (Strobele et al.
2012SPIE.8447E..37S 2012SPIE.8447E..37S). Conditions were generally excellent, with clear
sky and sub-arcsecond image quality in dark time. We acquired a total
of 24 exposures, each of 900s, for a total on-source exposure time of
6h. In between exposures, we applied small offsets (∼3-4arcsec) and
15deg rotations to reduce systematic errors.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 47 52 Spectroscopic redshifts and coordinates for
continuum-detected sources
table2.dat 96 21 Properties of the emission line galaxies
detected at S/N≥6 in the MUSE cube between
6100 and 7900Å
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Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 16 A16 --- Name Source designation (JHHMMSS.s+DDMMSS)
18- 27 F10.6 deg RAdeg Right ascension (J2000)
29- 38 F10.6 deg DEdeg Declination (J2000)
40- 45 F6.4 --- z Redshift
47 I1 --- QF [2/6] Quality flag
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 2 I2 --- ID [1/21] Galaxy identifier
4- 5 I2 h RAh Right ascension (J2000)
7- 8 I2 min RAm Right ascension (J2000)
10- 15 F6.3 s RAs Right ascension (J2000)
17 A1 --- DE- Declination sign (J2000)
18- 19 I2 deg DEd Declination (J2000)
21- 22 I2 arcmin DEm Declination (J2000)
24- 28 F5.2 arcsec DEs Declination (J2000)
30 A1 --- l_imag Limit flag on imag
32- 35 F4.1 mag imag i-band magnitude
37- 39 F3.1 mag e_imag ? Error on imag
41 A1 --- l_UVMAG Limit flag on UVMAG
43- 47 F5.1 mag UVMAG ? Absolute UV magnitude
49- 51 F3.1 mag e_UVMAG ? Error on UVMAG
53- 57 F5.2 10-21W/m2 Fline Line flux
59- 62 F4.2 10-21W/m2 e_Fline Error on Fline
64- 69 F6.2 10+33W Lline Line luminosity
71- 75 F5.2 10+33W e_Lline Error on Lline
77- 82 F6.4 --- z Redshift
84- 86 I3 kpc2 Area ? Area (1)
88 I1 --- Class [1/2] Confidence class (2)
90- 94 A5 --- Type Galaxy type (3)
96 A1 --- Flag Flag (4)
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Note (1): The area is calculated for each source out to a surface brightness
level of 10-18.25erg.s-1.cm-2.arcsec-2
Note (2): Class as follows:
1 = Objects in class 1 have integrated S/N≥7 in the mean coadd, are
detected with S/N>3 within independent coadds of only half of the
exposures, and the S/N of these two subsets agree within 50 per cent of
their value. This class contains sources with the highest purity at the
expense of completeness.
2 = Objects in class 2 obey a similar classification, but include the
remaining objects with 6=<S/N<7, which raises the completeness at the
possible expense of the purity.
Note (3): Type as follows:
LAE = Ly α emitting galaxy (15/21)
[OII] = [OII] emitter (6/21)
Note (4): Flag as follows:
a = Overlaps with emitter 4 in projection, but appears at different redshift
b = Classification uncertain
c = Overlaps with continuum source 108 in projection, but appears at
different redshift
d = Overlaps in part with continuum source 150 in projection, but appears
at different redshift
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History:
From electronic version of the journal
(End) Ana Fiallos [CDS] 11-May-2023