J/MNRAS/484/5049 DECam Survey of Scorpius Centaurus (Moolekamp+, 2019)
DECam survey for low-mass stars and substellar objects in the UCL and LCC
subgroups of the Sco-Cen OB Association (SCOCENSUS).
Moolekamp F.E., Mamajek E.E., James D.J., Luhman K.L., Pecaut M.J.,
Metchev S.A., Bell C.P.M., Denbo S.R.
<Mon. Not. R. Astron. Soc., 484, 5049-5071 (2019)>
=2019MNRAS.484.5049M 2019MNRAS.484.5049M (SIMBAD/NED BibCode)
ADC_Keywords: Stars, M-type; Stars, masses; Photometry, ugriz
Keywords: techniques: image processing - techniques: photometric -
proper motions - (stars:) brown dwarfs -
stars: luminosity function, mass function
Abstract:
Using images taken with the Dark Energy Camera (DECam), the first
extensive survey of low mass and substellar objects is made in the
∼15-20Myr Upper Centaurus Lupus (UCL) and Lower Centaurus Crux
(LCC) subgroups of the Scorpius-Centaurus OB Association (Sco-Cen).
Due to the size of our data set (>2Tb), we developed an extensive open
source set of python libraries to reduce our images, including
astrometry, coaddition, and PSF photometry. Our survey consists of
29x3deg2 fields in the UCL and LCC subgroups of Sco-Cen and the
creation of a catalogue with over 11 million point sources. We create
a prioritized list of UCL and LCC candidate members, with 118 best and
another 348 good candidates. We show that the luminosity and mass
functions of our low mass and substellar candidates are consistent
with measurements for the younger Upper Scorpius subgroup and
estimates of a universal IMF, with spectral types ranging from M1 down
to L1.
Description:
Photometric and estimated properties of M and L dwarfs in the UCL and
LCC subgroups of Scorpius Centaurus. izY magnitudes are PSF magnitudes
made on DECam images and calibrated using SDSS reference fields. ID's
for all cross-matched objects in external catalogs (2MASS, AllWISE,
etc) are also given, as entries in those catalogs were used to
estimate the proper motions of our stellar and substellar candidates
as described in the paper.
Some fields were observed multiple times with DECam, in which case we
list proper motions estimated using decam observations only, in
addition to proper motions using our DECam observations and reference
catalogs.
Using the Baraffe et al. (2015A&A...577A..42B 2015A&A...577A..42B) models combined with
our photometric measurements we estimated mass, Teff, age, spectral
type, atmospheric extinction, and distance to each object. The tables
also includes flags used for processing, including a confidence
estimate as described in the paper. Some starts were saturated in the
200s exposures, so shorter 7s exposures were used and sources with
entries from the short exposures are marked with a "shortexp" column
name.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
catalog.dat 1040 662 Catalog
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See also:
B/denis : The DENIS database (DENIS Consortium, 2005)
II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)
II/328 : AllWISE Data Release (Cutri+ 2013)
I/322 : UCAC4 Catalogue (Zacharias+, 2012)
I/284 : The USNO-B1.0 Catalog (Monet+ 2003)
I/305 : The Guide Star Catalog, Version 2.3.2 (GSC2.3) (STScI, 2006)
Byte-by-byte Description of file: catalog.dat
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Bytes Format Units Label Explanations
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1- 13 A13 --- ID ID of each candidate
15- 20 F6.1 yr Epoch [2015.4] Epoch used in the RA and DE
positions
22- 39 F18.14 deg RAdeg Right ascension (ICRS) at Ep=2015.4
41- 60 F20.17 mas e_RAdeg Estimated RA error
62- 80 F19.15 deg DEdeg Declination (ICRS) at Ep=2015.4
82- 101 F20.16 mas e_DEdeg Estimated DE error
103- 120 F18.15 mag imag PSF i-band magnitude
122- 143 E22.20 mag e_imag Estimated error in i
145- 147 F3.1 --- f_imag [0/1] True if this record was from
a 7s exposure
149- 166 F18.15 mag zmag PSF z-band magnitude
168- 189 E22.20 mag e_zmag Estimated error in z
191- 193 F3.1 --- f_zmag [0/1] True if this record was from
a 7s exposure
195- 212 F18.15 mag z-Y ? z-Y color index
214- 235 E22.20 mag e_z-Y ? Estimated error in z-Y color index
237- 254 F18.15 mag Ymag ? PSF Y-band magnitude
256- 277 E22.20 mag e_Ymag ? Estimated error in Y
279- 281 F3.1 --- f_Ymag [0/1] True if this record was from
a 7s exposure
283- 302 F20.16 mas/yr pmRAD ? Proper motion RA component using
only DECam observations
304- 325 F22.16 mas/yr e_pmRAD ? Error in pmRAD measurement
327- 346 F20.16 mas/yr pmDED ? Proper motion RA component using
only DECam observations
348- 369 F22.16 mas/yr e_pmDED ? Error in pmDED measurement
371- 390 F20.16 mas/yr pmRAR ? References proper motion RA component
392- 417 F26.17 mas/yr e_pmRAR ? Error in pmRAR measurement
419- 440 F22.17 mas/yr pmDER ? References proper motion DE component
442- 467 F26.17 mas/yr e_pmDER ? Error in pmDER measurement
469- 484 A16 --- 2MASS 2MASS ID (HHMMSsss+DDMMSSs)
486- 504 A19 --- AllWISE AllWISE ID (JHHMMSS.ss+DDMMSS.s)
506- 515 A10 --- UCAC4 UCAC4 ID (FFF_NNNNNN)
517- 528 A12 --- USNOB1 USNOB1 ID (FFFF-NNNNNNN)
530- 539 A10 --- GSC GSC ID
541- 556 A16 --- DENIS DENIS ID (JHHMMSS.s+DDMMSS)
558- 560 A3 --- frame2013 DECam CCD for 2013 epoch observation
562- 564 A3 --- frame2015 DECam CCD for 2015 epoch observation
566- 568 F3.1 --- badwp2013 [0/1]? True if the SEP windowed position
algorithm failed for the 2013 position
570- 572 F3.1 --- badwp2015 [0/1] True if the SEP windowed position
algorithm failed for the 2015 position
574- 576 F3.1 --- badid2013 [0/1]? True if the 2013 measurement is bad
578- 580 F3.1 --- badid2015 [0/1] True if the 2015 measurement is bad
582- 585 A4 --- Obj The "OBJECT" used to identify the field
in the DECam observation header
587- 589 A3 --- subgroup Subgroup of Sco-Cen containing this
candidate
591- 593 F3.1 --- best-pm [0/1]? True for high quality PM
measurements
595- 597 F3.1 --- no-pm [0/1] True when only observed in 1 epoch
599- 601 F3.1 --- low-mag [0/1] True when the source has very low SN
603- 605 F3.1 --- best [0/1]? Source has good decam PM and ref PM
607- 609 F3.1 --- goodpmD [0/1]? True for reliable DECam
proper motions
611- 613 F3.1 --- goodpmR [0/1]? True for reliable reference
proper motions
615- 634 F20.18 Msun Mass Estimated mass
637- 658 F22.20 Msun e_Mass Lower bound of estimated mass
661- 682 E22.20 Msun E_Mass Upper bound of estimated mass
684- 704 F21.16 Myr Age Estimted age
707- 728 F22.17 Myr e_Age Lower bound on estimated age
731- 752 F22.17 Myr E_Age Upper bound on estimated age
754- 772 F19.15 pc Dist Estimated distance
774- 792 F19.16 pc e_Dist Lower bound on estimated distance
794- 812 F19.16 pc E_Dist Upper bound on estimated distance
814- 831 F18.13 K Teff Estimated Teff
833- 851 F19.15 K e_Teff Lower bound on estimated Teff
853- 871 F19.15 K E_Teff Upper bound on estimated Teff
873- 890 F18.16 [Lsun] logg Estimated surface gravity
892- 911 F20.18 [Lsun] e_logg Lower bound on estimated logg
913- 932 F20.18 [Lsun] E_logg Upper bound on estimated logg
934- 938 A5 --- SpType Estimated spectral type
940- 944 A5 --- e_SpType Earliest possible spectral type
946- 950 A5 --- E_SpType Latest possible spectral type
952- 971 F20.18 mag Av Estimated extinction
973- 992 F20.18 mag e_Av Lower bound on estimated Av
994-1013 F20.18 mag E_Av Upper bound on estimated Av
1015-1034 F20.16 --- chi2 chi2 of the model fit
1036-1040 A5 --- conf How confident we are that this source
is a member of Sco-Cen
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Acknowledgements:
Frea Moolekamp, fred.moolekamp(at)gmail.com
(End) Patricia Vannier [CDS] 18-Dec-2020