J/ApJ/815/57 Follow-up spectroscopy of Lyα 3<z<7 emitters (U+, 2015)
A correlation between Lyα spectral line profile and
rest-frame UV morphology.
U V., Hemmati S., Darvish B., Mobasher B., Nayyeri H., Dickinson M.,
Stern D., Spinrad H., Mallery R.
<Astrophys. J., 815, 57 (2015)>
=2015ApJ...815...57U 2015ApJ...815...57U (SIMBAD/NED BibCode)
ADC_Keywords: Galaxies, spectra ; Redshifts ; Morphology ; Interstellar medium
Keywords: galaxies: evolution; galaxies: high-redshift; galaxies: ISM
Abstract:
We explore the relationship between the spectral shape of the
Lyα emission and the UV morphology of the host galaxy using a
sample of 304 Lyα-emitting BVi-dropouts at 3<z<7 in the Great
Observatories Origins Deep Survey and Cosmic Evolution Survey fields.
Using our extensive reservoir of high-quality Keck DEIMOS spectra
combined with Hubble Space Telescope WFC3 data, we measure the
Lyα line asymmetries for individual galaxies and compare them to
axial ratios measured from observed J- and H-band (restframe UV)
images. We find that the Lyα skewness exhibits a large scatter
at small elongation (a/b<2), and this scatter decreases as the axial
ratio increases. Comparison of this trend to radiative transfer models
and various results from the literature suggests that these
high-redshift Lyα emitters are not likely to be intrinsically
round and symmetric disks, but they probably host galactic outflows
traced by Lyα emitting clouds. The ionizing sources are
centrally located, and the optical depth is a good indicator of the
absorption and scattering events on the escape path of Lyα
photons from the source. Our results find no evidence of evolution in
Lyα asymmetry or axial ratio with look-back time.
Description:
The Keck spectroscopic follow-up campaign of high-redshift galaxies in
the GOODS+CANDELS fields has been an ongoing project since 2005.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 57 304 Spectroscopic properties of Lyα-emitters
(LAEs)
--------------------------------------------------------------------------------
See also:
II/284 : COSMOS Multi-Wavelength Photometry Catalog (Capak+, 2007)
II/318 : GOODS Source Catalogs release r2.0z (Giavalisco+ 2008)
II/261 : GOODS initial results (Giavalisco+, 2004)
J/ApJ/803/34 : z∼4-10 galaxies from HST legacy fields (Bouwens+, 2015)
J/ApJS/207/24 : GOODS-S CANDELS multiwavelength catalog (Guo+, 2013)
J/ApJ/760/128 : Lyα emission from 4<z<6 COSMOS sources (Mallery+, 2012)
J/ApJ/758/135 : DEEP2 galaxies with UV spectra in the EGS (Kornei+, 2012)
J/ApJ/753/95 : LAE galaxies in the ECDF-S at z∼2.1 and z∼3.1 (Bond+, 2012)
J/ApJ/751/29 : Lyα profiles of LAEs at z=3.1 (Yamada+, 2012)
J/ApJ/743/9 : z=3.1 LAEs morphological properties (Gronwall+, 2011)
J/ApJ/742/3 : Photometric catalogs for ECDF-S and CDF-N (Rafferty+, 2011)
J/ApJ/725/394 : High-redshift Lyα emitters (Hu+, 2010)
J/ApJ/706/762 : LAEs at z∼4.5 in the LALA Cetus field (Wang+, 2009)
J/ApJ/696/546 : Lyα emitters at z∼4.86 (Shioya+, 2009)
J/A+A/498/13 : Lyman-α emitters from redshifts z∼2-3 (Nilsson+, 2009)
J/ApJS/172/523 : COSMOS field Lyα emitters at z∼5.7 (Murayama+, 2007)
J/AJ/132/1729 : Hubble Ultra Deep Field BVI-dropout sources (Beckwith+, 2006)
J/ApJ/648/7 : LAEs at z=6.5 in Subaru Deep Field (Kashikawa+, 2006)
J/PASJ/58/313 : Lyα emitters in the SUBARU Deep Field (Shimasaku+, 2006)
J/A+A/431/793 : Ly-alpha emitters around MRC 0316-257 (Venemans+, 2005)
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 I3 --- Seq Running sequence number
5- 13 F9.5 deg RAdeg Right Ascension in decimal degrees (J2000)
15- 23 F9.5 deg DEdeg Declination in decimal degrees (J2000)
25- 31 A7 --- Type BVi Dropout type (1)
33- 37 F5.3 --- z [3.2/7.3] Spectroscopic redshift
39 A1 --- zflag [AB-] Redshift quality flag (A=most reliable) (2)
41- 45 F5.3 --- Skew [0/9.4] Skewness
47- 51 F5.3 --- e_Skew [0.01/5] Uncertainty in Skew
53- 57 F5.3 --- a/b [1/3.5] Axial Ratio
--------------------------------------------------------------------------------
Note (1): The following color-color selection as adopted from, e.g.,
Beckwith et al. (2006, J/AJ/132/1729) and
Stark et al. (2009ApJ...697.1493S 2009ApJ...697.1493S), are ideal for identifying
candidate star-forming galaxies at z>3:
B-dropouts = B435-V606>1.1+V606-z850,
B435-V606>1.1,
V606-z850<1.6,
S/N(V606)>5,
and S/N(i775)>3.
V-dropouts = V606-i775>1.47+0.89(i775-z850) or 2,
V606-i775>1.2,
i775-z850<1.3,
S/N(z850)>5,
and S/N(B435)<3, or B435-i775>V606-i775+1
i-dropouts = i775-z850>1.3,
S/N(z850)>5,
and S/N(V606)<2, or V606-z850>2.8.
We classify 188 sources as "Other": these are Lyα-emitting
sources not classified as dropouts. The non-dropouts in GOODS are
likely too faint for color selection, whereas those in COSMOS were
primarily selected in narrowband surveys.
See section 2 for further explanations.
Note (2): For the GOODS fields, quality code "A" indicates the most reliable
redshifts, whereas the "B" redshifts are most likely correct. See
text for details. Redshifts of the COSMOS sources have previously
been published in Mallery et al. (2012, J/ApJ/760/128).
--------------------------------------------------------------------------------
History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 07-Mar-2016