J/AJ/132/231 MMT hectospec redshift survey of 24um sources (Papovich+, 2006)
An MMT hectospec redshift survey of 24 µm sources in the
Spitzer first look survey.
Papovich C., Cool R., Eisenstein D., Le Floc'h E., Fan X.,
Kennicutt R.C.JR, Smith J.D.T., Rieke G.H., Vestergaard M.
<Astron. J., 132, 231-241 (2006)>
=2006AJ....132..231P 2006AJ....132..231P
ADC_Keywords: Surveys ; Galaxies, IR
Keywords: galaxies: high-redshift - infrared: galaxies
Abstract:
We present a spectroscopic survey using the MMT Hectospec fiber
spectrograph of 24um sources selected with the Spitzer Space Telescope
in the Spitzer First Look Survey. We report 1296 new redshifts for
24um sources, including 599 with fnu(24um)≥1mJy. Combined with 291
additional redshifts for sources from the Sloan Digital Sky Survey
(SDSS), our observing program was highly efficient and is ∼90%
complete for i≤21mag and fnu(24um)≥1mJy and 35% complete for
i≤20.5mag and 0.3mJy≤fnu(24um)<1.0mJy. Our Hectospec survey
includes 1078 and 168 objects spectroscopically classified as galaxies
and QSOs, respectively. Combining the Hectospec and SDSS samples, we
find 24 mselected galaxies to zgal≤0.98 and QSOs to zQSO≤3.6, with
mean redshifts of =0.27 and <zQSO≥1.1. As part of this
publication, we include the redshift catalogs and the reduced spectra;
these are also available through the NASA/IPAC Infrared Science Archive.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 64 5 Target Hectospec Fields
table3.dat 181 7222 SDSS-Matched 24 micron Catalog
table4.dat 102 291 *SDSS-Spectroscopic Catalog
table5.dat 106 1317 *Hectospec-Spectroscopic Catalog
sp/* . 1317 Spectra as ascii files (extracted from FITS files)
fits/* . 5 Multi-extension FITS files containing the
calibrated, reduced spectra from the
MMT/Hectospec survey (see detailed description in
the "Description of files: fits/*" section below)
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Note on table4.dat, table5.dat: null records were removed from original tables.
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Description of files: fits/*
The files spHect-*-0300.fits files are multi-extension FITS files
containing the calibrated, reduced spectra from the MMT/Hectospec
survey. The number of each file (131-135) corresponds to the
observations from each field (see table 2 in the manuscript). There
are 10 HDU extensions in each file. Extensions 1-5 contain information
for each spectrum; these have dimension of npixel x nfiber, where
npixel=4608 (the number of pixels in the spectrum) and nfiber=300 (the
number of fibers). Extension 6 contains targeting information for each
fiber; Extensions 7-10 contain information used in the data reduction.
For the discussion here, we assume the first element in the FITS
tables is entry 1,1.
The HDUs are:
1 = Float array, 4608x300; Wavelength solution in Angstroms
2 = Float array, 4608x300; Flux density of the spectrum in units of
10-17erg/s/cm2/Angstrom (10-19W/m2/nm)
3 = Float array, 4608x300; Inverse Variance for the flux density
4 = Float array, 4608x300; mask of warning flags for each pixel combined
between all exposures with logical OR
5 = Float array, 4608x300; mask of warning flags for each pixel combined
between all exposures with logical AND
6 = targeting information for the observation. It contains
OBJTYPE = Type of fiber assignment:
TARGET = target source
SKY = sky fiber
SPECTROPHOTO_STD = F Star Standard
REJECT = sky fiber was rejected due to possible source
RA = Right Ascension (J2000) of fiber
DEC = Declination (J2000) of fiber
FIBERID = Maps aperture to physical fiber on Hectospec
RMAG = SDSS r-band magnitude of source
RAPMAG = Estimate of the r-band magnitude measured through
an aperture with 1.5" diameter
ICODE = Targeting flags for the observations in Integer format
RCODE = Not used
BCODE = Not used
MAG = SDSS ugriz magnitudes for objects with
OBJTYPE≡SPECTROPHOTO_STD
XFOCAL = x-position of fiber on Hectospec focal plane
YFOCAL = y-position of fiber on Hectospec focal plane
FRAMES = Bookkeeping value from reductions
EXPID = Name of highest-quality exposure
TSOBJID = Not used
TSOBJ_MAG = Bookkeeping values used in spectra fluxing
EBV_SFD = E(B-V) for fiber derived from the
Schelgel, Finkbeiner and Davis (1998) maps
Extensions 7-10 contain information on the flat field and sky spectrum
for the reduction. They are not useful for most applications.
7 = Structure containing B-Spline parameters for the sky spectrum derived
for Fibers 1-150. This structure is of the form utilized by the IDL
routine (in the IDLUTILS package) BSPLINE_VALU.
8 = Float array [npixel,150] array containing the auxiliary flat-field
correction derived for each fiber (1-150) based on the strength of
various sky lines as part of the reductions.
9 = Same as Extension 6, but this structure contains the parameters
defining the best fit sky spectrum appropriate for Fibers 151-300.
10 = Same as Extension 8, but this image contains the scales for
Fibers 151-300.
Objects have their FIELD and FIBER value in the table 5 of the
manuscript. For example, the wavelength and fflux information for the
spectrum of an object with FIELD=132 and FIBER=200 would be HDU
extensions 1 and 2 of the data in spHect-132-0300.fits[*,200].
System requirements: Software to read Binary fits tables (e.g., IDL
mrdfits function, or IRAF/STSDAS tables package).
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See also:
http://www.sdss.org/ : SDSS Home page
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- Field Field number
5- 6 I2 h RAh Right ascension (J2000)
8- 9 I2 min RAm Right ascension (J2000)
11- 14 F4.1 s RAs Right ascension (J2000)
16 A1 --- DE- Declination sign (J2000)
17- 18 I2 deg DEd Declination (J2000)
20- 21 I2 arcmin DEm Declination (J2000)
23- 24 I2 arcsec DEs Declination (J2000)
26- 27 I2 min TExp Exposure time
29- 38 A10 "YYYY/MM/DD" ObsDate Observation date
40- 43 F4.2 --- AirMass AirMass
45- 64 A20 --- FileName Name of the FITS file, in subdirectory fits
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 4 I4 --- [PCE2006] Running identification number
6- 14 F9.5 deg RAdeg SDSS Right Ascension in decimal Degrees (J2000)
16- 23 F8.5 deg DEdeg SDSS Declination in decimal Degrees (J2000)
25- 28 I4 --- Run SDSS run number
30- 31 I2 --- reRun SDSS rerun number
33 I1 --- CamCol [1/6] SDSS camcol number
35- 36 I2 --- Field SDSS field number
38- 41 I4 --- ObjID SDSS object identification
43- 49 F7.2 pix ObjRow SDSS row pixel position
51- 57 F7.2 pix ObjCol SDSS column pixel position
59- 63 F5.2 mag Imod SDSS i combined model total dereddened mag.
65- 69 F5.2 mag u-gmod SDSS (u-g) combined model dereddened color
71- 75 F5.2 mag g-rmod SDSS (g-r) combined model dereddened color
77- 81 F5.2 mag r-imod SDSS (r-i) combined model dereddened color
83- 87 F5.2 mag i-zmod SDSS (i-z) combined model dereddened color
89- 93 F5.2 mag rPetro SDSS r Petrosian dereddened magnitude
95- 99 F5.2 mag uPSF SDSS u PSF dereddened magnitude
101-105 F5.2 mag gPSF SDSS g PSF dereddened magnitude
107-111 F5.2 mag rPSF SDSS r PSF dereddened magnitude
113-117 F5.2 mag iPSF SDSS i PSF dereddened magnitude
119-123 F5.2 mag zPSF SDSS z PSF dereddened magnitude
125-129 F5.2 mag rFib SDSS r fiber magnitude
131-135 F5.2 mag iFib SDSS i fiber magnitude
137-141 F5.3 mag Ar Extinction in r-band, used for dereddening
143-147 F5.3 arcsec Seeing Seeing in r
149 I1 --- Tf Hectospec target flag (G1)
151-156 F6.3 mJy F24um MIPS 24 micron flux density
158-162 F5.3 mJy e_F24um Error in F24um (2)
164-172 F9.5 deg RAMdeg MIPS Right Ascension in decimal Degrees (J2000)
174-181 F8.5 deg DEMdeg MIPS Declination in decimal Degrees (J2000)
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Note (2): Does not include correlated pixel noise and thus
underestimates the error.
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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- 4 I4 --- [PCE2006] Running identification number
6- 14 F9.5 deg RAdeg Right Ascension (J2000)
16- 23 F8.5 deg DEdeg Declination (J2000)
25- 27 I3 --- Field SDSS field number
29- 31 I3 --- Fiber SDSS fiber identification number
33- 37 I5 --- reRun SDSS rerun number
39- 47 I9 --- Tcode SDSS target code, in decimal (1)
49- 58 A10 --- H-Tcode SDSS Hexadecimal target code (1)
60- 65 A6 --- Class Spectroscopic classification (G2)
67- 77 A11 --- SClass Spectroscopic subclass (G3)
79- 86 F8.5 --- z Redshift
88- 94 F7.5 --- e_z ?=0.00000 Error in z
96 I1 --- f_z [0] Flag on z (2)
98-102 F5.3 --- chi2 Reduced chi-squared of fit
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Note (1): NOT the same as for Hectospec.
Note (2): Redshift Warning flag, values of 0 are safe.
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Byte-by-byte Description of file: table5.dat
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Bytes Format Units Label Explanations
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1- 4 I4 --- [PCE2006] Running identification number
6- 14 F9.5 deg RAdeg SDSS Right Ascension in decimal Degrees (J2000)
16- 23 F8.5 deg DEdeg SDSS Declination in decimal Degrees (J2000)
25- 27 I03 --- Field Hectospec field
29- 31 I03 --- Fiber Hectospec fiber
33- 35 I3 --- reRun Hectospec reduction rerun
37 I1 --- Tcode Hectospec target code, edited in decimal (G1)
39- 42 A4 --- H-Tcode Hectospec hexadecimal target code (G1)
44- 49 A6 --- Class Spectroscopic classification (G2)
51- 59 A9 --- SClass Spectroscopic subclass (G3)
61- 68 F8.5 --- z Redshift
70- 76 F7.5 --- e_z ?=9.99999 Error in z
78- 79 I2 --- f_z Redshift Warning flag, 0 when no problem
81- 86 F6.3 --- chi2 Reduced chi-squared of fit
88- 94 F7.3 --- Dfit Difference between relative to the next best fit
96-102 F7.3 --- S/N Signal-to-Noise ratio for spectrum
104 I1 --- Vflg [0/1] Visual inspection flag: 1=secure redshift,
0=insecure or dubious redshift
106 I1 --- Vfix [0/1] 1=redshift changed after visual inspection
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Byte-by-byte Description of file: sp/*
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Bytes Format Units Label Explanations
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2- 8 F7.2 0.1nm lambda Wavelength
10- 19 E10.4 0.1aW/m2/nm Flux Flux density, in 10^-17 erg/s/cm^2/Å
21- 28 E8.2 --- var-1 Inverse of variance (weight) of Flux
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Global notes:
Note (G1): Hectospec target flag as follows:
1 = calibration star
2 = Primary Sample
4 = Secondary Sample
8 = Tertiary Sample
9 = not specified (one object, 7106)
0 = other
Note (G2): Spectroscopic classification:
QSO, STAR, GALAXY or x when not observed
Note (G3): Spectroscopic subclass indicates the type of galaxy or
the spectral type for stars. x when not observed.
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History:
* 31-Aug-2007: From electronic version of the journal
* 30-Dec-2007: Added hecto-spectra in sub-directory sp,
created from (correct) FITS files
(End) Greg Schwarz [AAS], Patricia Vannier+Francois Ochsenbein [CDS] 31-Aug-2007