J/ApJS/207/37 IR sources spectroscopy in the AKARI NEP (Shim+, 2013)
Hectospec and Hydra spectra of infrared luminous sources in the AKARI North
Ecliptic Pole Survey field.
Shim H., Im M., Ko J., Jeon Y., Karouzos M., Kim S.J., Lee H.M.,
Papovich C., Willmer C., Weiner B.J.
<Astrophys. J. Suppl. Ser., 207, 37 (2013)>
=2013ApJS..207...37S 2013ApJS..207...37S
ADC_Keywords: Redshifts ; Spectroscopy ; Surveys ; Galaxies, IR ;
Active gal. nuclei
Keywords: catalogs - galaxies: distances and redshifts - infrared: galaxies -
surveys - techniques: spectroscopic
Abstract:
We present spectra of 1796 sources selected in the AKARI North
Ecliptic Pole Wide Survey field, obtained with MMT/Hectospec and
WIYN/Hydra, for which we measure 1645 redshifts. We complemented the
generic flux-limited spectroscopic surveys at 11 µm and 15 µm,
with additional sources selected based on the MIR and optical colors.
In MMT/Hectospec observations, the redshift identification rates are
∼80% for objects with R < 21.5 mag. On the other hand, in WIYN/Hydra
observations, the redshift identification rates are ∼80% at R
magnitudes brighter than 19 mag. The observed spectra were classified
through the visual inspection or from the line diagnostics. We
identified 1128 star-forming or absorption-line-dominated galaxies,
198 Type-1 active galactic nuclei (AGNs), 8 Type-2 AGNs, 121 Galactic
stars, and 190 spectra in unknown category due to low signal-to-noise
ratio. The spectra were flux-calibrated but to an accuracy of
0.1-0.18dex for most of the targets and worse for the remainder. We
derive star formation rates (SFRs) from the mid-infrared fluxes or
from the optical emission lines, showing that our sample spans an SFR
range of 0.1 to a few hundred M☉/yr. We find that the extinction
inferred from the difference between the IR and optical SFR increases
as the IR luminosity increases but with a large scatter.
Description:
Most of the targets for the spectroscopic observation were selected
from the optical to mid-infrared band-merged photometry catalog over
the NEP-Wide field (Kim et al. 2012, Cat. J/A+A/548/A29).
The observations, with the MMT/Hectospec spectrograph, were executed
in queue mode: a total of five configurations were observed between
2008 May and November, with each configuration covering an area within
a 1deg diameter circle. The observations used the 270 line/mm grating
covering ∼3700Å to ∼8500Å, with a spectral resolution of about
6.2Å.
We obtained optical spectra using the Hydra multi-object spectrograph
on WIYN, the 3.5m telescope at the Kitt Peak National Observatory, on
the nights of 2008 June 27-30. The covered wavelength range is
4500-9000Å, yet the spectrum quality is very poor beyond 8000Å.
We used 98 red fibers feeding the bench spectrograph with a
316 lines/mm grating, yielding a spectral resolution of 5.7Å.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table3.dat 88 1796 Optical redshifts catalog over NEP-Wide Survey
table4.dat 118 1796 Line flux measurements for selected emission lines
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See also:
J/A+A/548/A29 : IR source catalog of AKARI NEP-Wide field (Kim+, 2012)
J/A+A/537/A24 : AKARI NEP-Deep field mid-IR source catalogue (Takagi+, 2012)
J/ApJS/190/166 : Optical catalog of AKARI NEP-wide survey (Jeon+, 2010)
J/A+A/517/A54 : 20cm survey of the AKARI NEP (White+, 2010)
J/PASJ/59/S529 : NEP deep survey at 11um (Lee+, 2007)
J/ApJS/172/583 : NEP source catalog (Hwang+, 2007)
Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 4 A4 --- --- [NEP_]
5- 22 A18 --- NEP Object identifier (JHHMMSS.s+DDMMSS.s)
24- 32 F9.5 deg RAdeg [266.81/273.37] Right Ascension (J2000)
34- 41 F8.5 deg DEdeg [65.34/67.74] Declination (J2000)
43- 47 F5.2 mag Rmag [13.86/24.25]?=99 R-band AB magnitude (G1)
49- 55 F7.4 --- z [-0.02/3.86]?=-1 Redshift
57 I1 --- q_z [1/4] Quality flag on z, 4=best (1)
59- 69 A11 --- Field Observation field; configuration (nep0N for
WIYN/Hydra or nep-hecto-N for MMT/Hectospec)
71- 73 I3 --- Fiber [1/300] Fiber identifier
75- 81 A7 --- Class Classification of spectrum (2)
83- 88 A6 --- n_z emission/absorption redshift (3)
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Note (1): Quality flag as follows:
4 = Clearly identified using more than two significant spectral features;
3 = Identified using more than two spectral features with less S/N;
2 = Identified assuming single, weak spectral feature
such as continuum break;
1 = Redshift could not be measured.
Note (2): Spectrum classification through visual inspection as:
TYPE1 = the object shows broad emission lines, thus is considered to be
Type-1 AGN (198 sources).
TYPE2 = the object is classified to be narrow-line AGN according to the line
ratios (BPT diagram; Figure 10) (8 sources).
GALAXY = the object is considered to be a galaxy, not dominated by AGN
features (1128 sources).
STAR = Galactic star (121 sources).
Note (3): Redshift identification done from:
em = emission lines;
abs = absorption lines;
em+abs = both lines used.
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Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 A4 --- --- [NEP_]
5- 22 A18 --- NEP Object identifier (JHHMMSS.s+DDMMSS.s)
24- 28 F5.2 mag Rmag [13.86/24.25]?=99 R-band AB magnitude (G1)
30- 36 F7.2 10-20W/m2 FOII [1.1/2482]? The [OII] 3727A line flux (4)
37 A1 --- f_FOII [o] Line redshifted (5)
39- 45 F7.2 10-20W/m2 FHb [0.9/1637]? Hβ line flux (4)
46 A1 --- f_FHb [o] Line redshifted (5)
48- 54 F7.2 10-20W/m2 FOIII4959 [0.3/684]? [OIII] 4959Å line flux (4)
55 A1 --- f_FOIII4959 [o] Line redshifted (5)
57- 63 F7.2 10-20W/m2 FOIII5007 [0.9/1913]? [OIII] 5007Å line flux (4)
64 A1 --- f_FOIII5007 [o] Line redshifted (5)
66- 72 F7.2 10-20W/m2 FOI [-1.1/175]? [OI] 6300Å line flux (4)
73 A1 --- f_FOI [o] Line redshifted (5)
75- 81 F7.2 10-20W/m2 FNII6548 [-1.8/245]? [NII] 6548Å line flux (4)
82 A1 --- f_FNII6548 [o] Line redshifted (5)
84- 90 F7.2 10-20W/m2 FHa [0.6/1090]? Hα line flux (4)
91 A1 --- f_FHa [o] Line redshifted (5)
93- 99 F7.2 10-20W/m2 FNII6584 [0.2/377]? [NII] 6584Å line flux (4)
100 A1 --- f_FNII6584 [o] Line redshifted (5)
102-108 F7.2 10-20W/m2 FSII6716 [-3.7/262]? [SII] 6716Å line flux (4)
109 A1 --- f_FSII6716 [o] Line redshifted (5)
111-117 F7.2 10-20W/m2 FSII6731 [1.8/335]? [SII] 6731Å line flux (4)
118 A1 --- f_FSII6731 [o] Line redshifted (5)
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Note (4): In units of 10-17erg/s/cm2.
Note (5):
o = The line is redshifted to longer wavelengths thus is not covered by our
spectroscopic observation.
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Globale note:
Note (G1): CFHT r-band magnitude (Hwang et al. 2007, Cat. J/ApJS/172/583)
or Maidanak R-band magnitude (Jeon et al. 2010, Cat. J/ApJS/190/166)
in AB magnitude system.
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 06-Sep-2013