J/ApJ/854/29 High-EW [OIII] and Hα emitters from 3D-HST (Maseda+, 2018)
The number density evolution of extreme emission line galaxies in 3D-HST:
results from a novel automated line search technique for slitless spectroscopy.
Maseda M.V., van der Wel A., Rix H.-W., Momcheva I., Brammer G.B.,
Franx M., Lundgren B.F., Skelton R.E., Whitaker K.E.
<Astrophys. J., 854, 29-29 (2018)>
=2018ApJ...854...29M 2018ApJ...854...29M (SIMBAD/NED BibCode)
ADC_Keywords: Galaxies, dwarf; Spectra, optical; Redshifts; Equivalent widths
Keywords: galaxies: dwarf; galaxies: evolution; galaxies: starburst
galaxies: statistics; methods: statistical; quasars: emission lines
Abstract:
The multiplexing capability of slitless spectroscopy is a powerful
asset in creating large spectroscopic data sets, but issues such as
spectral confusion make the interpretation of the data challenging.
Here we present a new method to search for emission lines in the
slitless spectroscopic data from the 3D-HST survey utilizing the
Wide-Field Camera 3 on board the Hubble Space Telescope. Using a novel
statistical technique, we can detect compact (extended) emission lines
at 90% completeness down to fluxes of 1.5(3.0)x10-17erg/s/cm2,
close to the noise level of the grism exposures, for objects detected
in the deep ancillary photometric data. Unlike previous methods, the
Bayesian nature allows for probabilistic line identifications, namely
redshift estimates, based on secondary emission line detections and/or
photometric redshift priors. As a first application, we measure the
comoving number density of Extreme Emission Line Galaxies (restframe
[OIII]λ5007 equivalent widths in excess of 500Å). We find
that these galaxies are nearly 10x more common above z∼1.5 than at
z≲0.5. With upcoming large grism surveys such as Euclid and WFIRST,
as well as grisms featured prominently on the NIRISS and NIRCam
instruments on the James Webb Space Telescope, methods like the one
presented here will be crucial for constructing emission line redshift
catalogs in an automated and well-understood manner.
Description:
The spectroscopic data comes from the 3D-HST survey
(see Skelton+ 2014, J/ApJS/214/24 and Momcheva+ 2016, J/ApJS/225/27),
designed to provide spectroscopy for four well-studied CANDELS
extragalactic fields: AEGIS, COSMOS, GOODS-S, and UDS. The data set is
supplemented by grism spectroscopy for GOODS-N (PI: B. Weiner).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 26 22 Grism and spectroscopic redshifts in GOODS-N
table4.dat 118 704 Confirmed high-EW [OIII] and/or Hα emitters
table5.dat 76 470 Plausible high-EW [OIII] emitters
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See also:
J/ApJS/172/70 : zCOSMOS-bright catalog, DR3 (Lilly+, 2007)
J/ApJ/668/853 : Spectroscopy of UltraStrong Emission Line gal. (Kakazu+, 2007)
J/AJ/135/1624 : PEARS emission-line galaxies (Straughn+, 2008)
J/ApJ/742/111 : Extreme emission-line galaxies in CANDELS (van der Wel+, 2011)
J/ApJ/772/48 : Emission-line galaxies from PEARS. II. (Pirzkal+, 2013)
J/A+A/568/L8 : VUDS extreme emission line 0.2≲z≲0.9 gal. (Amorin+, 2014)
J/ApJS/214/24 : 3D-HST+CANDELS catalog (Skelton+, 2014)
J/A+A/578/A105 : EELGs out to z∼1 in zCOSMOS (Amorin+, 2015)
J/ApJS/225/27 : 3D-HST Survey: grism spectra master catalog (Momcheva+, 2016)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 5 I5 --- ID [5878/32925] ID from
Skelton+ 2014, J/ApJS/214/24
(<[SWM2014] GOODS-N NNNNN> in Simbad)
7- 12 F6.4 --- zgrism [0.7/3.3] Grism redshift from this work
14- 19 F6.4 --- zspec [0.4/3.3] Spectroscopic redshift from
Skelton+ 2014, J/ApJS/214/24
21- 26 F6.4 --- z3DHST [0.3/3.24] Redshifts
from Momcheva+ 2016, J/ApJS/225/27
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Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
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1- 13 A13 --- ID Identifier from
Skelton+ (2014, J/ApJS/214/24)
15- 24 F10.6 deg RAdeg [34.2/215.2] Right ascension (J2000)
26- 36 F11.7 deg DEdeg [-28/62.4] Declination (J2000)
38- 42 F5.3 --- zgrism [0.66/2.4] Grism redshift
44- 50 F7.4 10-17mW/m2 FHa [0.037/19]? Hα flux; in
10-17erg/cm2/s
52- 59 F8.6 10-17mW/m2 e_FHa [0.0006/3]? FHa uncertainty
61- 67 F7.1 0.1nm EWHa [18.4/71700]? Restframe Hα
equivalent width in Å
69- 78 F10.2 0.1nm e_EWHa [6/1.13e+06]? EWHa uncertainty
80- 86 F7.4 10-17mW/m2 FOIII [0.04/23.4]? [OIII] Flux; in
10-17erg/cm2/s
88- 94 F7.5 10-17mW/m2 e_FOIII [0.006/4.1]? FOIII uncertainty
96- 105 F10.2 0.1nm EWOIII [5.98/1.84e+06]? Restframe
[OIII]equivalent width in Å
107- 118 F12.2 0.1nm e_EWOIII [2.7/7.4e+8]? EWOIII uncertainty
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Byte-by-byte Description of file: table5.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 13 A13 --- ID Identifier from
Skelton+ (2014, J/ApJS/214/24)
15- 24 F10.6 deg RAdeg [34.2/215.1] Right ascension (J2000)
26- 36 F11.7 deg DEdeg [-28/62.4] Declination (J2000)
38- 42 I5 0.1nm lambda [10830/16900] Wavelength
44- 49 F6.3 10-17mW/m2 Flux [0.5/19] Line Flux in 10-17erg/cm2/s
51- 55 F5.3 10-17mW/m2 e_Flux [0.13/3.3] Flux uncertainty
57- 63 I7 0.1nm EW [501/2880000] Restframe line equivalent
width in Å
65- 76 F12.1 0.1nm e_EW [79/2.2e+9] EW uncertainty
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History:
From electronic version of the journal
(End) Emmanuelle Perret [CDS] 02-Oct-2023