J/ApJS/275/27 Circumgalactic Lyα Nebulae at Cosmic Noon (Li+, 2024)
MAMMOTH-Subaru. II.
Diverse Populations of Circumgalactic Lyα Nebulae at Cosmic Noon.
Li M., Zhang H., Cai Z., Liang Y., Kashikawa N., Ma K., Fan X.,
Prochaska J.X., Emonts B.H.C., Wang X., Wu Y., Zhang S., Li Q.,
Johnson S.D., Yue M., Arrigoni Battaia F., Cantalupo S., Hennawi J.F.,
Kikuta S., Ning Y., Ouchi M., Shimakawa R., Wang B., Wang W., Zheng Z.,
Zheng Z.-Y.
<Astrophys. J. Suppl. Ser. 275, 27 (2024)>
=2024ApJS..275...27L 2024ApJS..275...27L (SIMBAD/NED BibCode)
ADC_Keywords: Galaxies, nearby ; Nebulae ; Ultraviolet
Keywords: high-redshift galaxies - galaxies - emission nebulae -
circumgalactic medium
Abstract:
Circumgalactic Lyα nebulae are gaseous halos around galaxies
exhibiting luminous extended Lyα emission. This work
investigates Lyα nebulae from deep imaging of ∼12 deg2 sky,
targeted by the MAMMOTH-Subaru survey. Utilizing the wide-field
capability of Hyper Suprime-Cam, we present one of the largest blind
Lyα nebula selections, including QSO nebulae, Lyα blobs,
and radio galaxy nebulae down to the typical 2σ Lyα
surface brightness of (5-10)x10-18erg/s/cm2/arcsec2.
The sample contains 117 nebulae with Lyα sizes of 40-400kpc, and
the most gigantic one spans about 365kpc, and is referred to as the
Ivory Nebula. Combining multiwavelength data, we investigate diverse
nebula populations and associated galaxies. We find a small fraction
of Lyα nebulae have QSOs (∼7%), luminous infrared galaxies
(LIRGs; ∼1%), and radio galaxies (∼2%). Remarkably, among the 28
enormous Lyα nebulae (ELANe) exceeding 100kpc, about 80% are
associated with UV-faint galaxies (MUV>-22), and are categorized as
Type II ELANe. We underscore that Type II ELANe constitute the
majority but remain largely hidden in current galaxy and QSO surveys.
Dusty starburst and obscured AGN activity are proposed to explain the
nature of Type II ELANe. The spectral energy distribution of stacking
all Lyα nebulae also reveals signs of massive dusty star-forming
galaxies with obscured AGNs. We propose a model to explain the dusty
nature where the diverse populations of Lyα nebulae capture
massive galaxies at different evolutionary stages undergoing violent
assembly. Lyα nebulae provide critical insights into the
formation and evolution of today's massive cluster galaxies at cosmic
noon.
Description:
In our survey, we perform deep NB imaging using NB387
(λc=3863Å, Δλ=55Å) and NB400
(λc=4003Å, Δλ=92Å) filters on the HSC, which
covers a 1.5° FOV in diameter. The NB filters enable us to detect
Lyα emission at the corresponding redshifts of z=2.177±0.023
and z=2.293±0.038, respectively. The line-of-sight depth of the
redshift slice is 62.3cMpc for NB387 and 97.8cMpc for NB400. The HSC g
band (λc=4754Å, Δλ=1395Å) is used for the
continuum estimate of the line-emitting sources.
We select 117 Lyα nebulae in an unbiased way and compile
multiwavelength data from UV to radio to achieve a panchromatic
perspective on the properties of Lyα nebulae.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table2.dat 77 117 Properties of Lyman-alpha Nebulae
--------------------------------------------------------------------------------
See also:
J/A+A/620/A202 : MAMMOTH-1 450 and 850um images (Arrigoni Battaia+, 2018)
Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 7 A7 --- Name Object name, MLANnnn
9- 13 A5 --- Field Field name
15- 23 F9.5 deg RAdeg Right Ascension in decimal degrees (J2000)
25- 32 F8.5 deg DEdeg Declination in decimal degrees (J2000)
34- 38 F5.2 mag NBmag Narrowband (NB387 or NB400) AB magnitude
40- 44 F5.2 mag gmag g band AB magnitude
46- 50 F5.1 arcsec2 Area Lyman-alpha emission isophotal area (1)
52- 56 F5.2 [10-7W] logLum log Lyman-alpha emission luminosity; erg/s (1)
58- 62 F5.1 kpc Size Lyman-alpha emission end-to-end size
64- 68 F5.3 --- Redshift ? Spectroscopic redshift if available
70- 77 A8 --- Comment Comments (2)
--------------------------------------------------------------------------------
Note (1): above the 2σ countour.
Note (2): Comments as follows:
T2 = Type II enormous Lyman-alpha nebulae;
R = With radio counterparts;
Q = Type-I QSO with spectrum;
IR = IR luminous objects identified by WISE;
Ivory = Nickname of MLAN1.
--------------------------------------------------------------------------------
History:
From electronic version of the journal
References:
Ma et al., Paper I 2024ApJ...961..102M 2024ApJ...961..102M
Zhang et al., Paper III 2024ApJ...961...63Z 2024ApJ...961...63Z
Zhang et al., Paper IV 2025ApJ...981...70Z 2025ApJ...981...70Z
Ma et al., Paper V 2024ApJ...961..102M 2024ApJ...961..102M
(End) Prepared by [AAS], Patricia Vannier [CDS] 12-Aug-2025