J/ApJS/186/259 Taurus Spitzer survey: new candidate members (Rebull+, 2010)
The Taurus Spitzer survey: new candidate Taurus members selected using
sensitive mid-infrared photometry.
Rebull L.M., Padgett D.L., McCabe C.-E., Hillenbrand L.A.,
Stapelfeldt K.R., Noriega-Crespo A., Carey S.J., Brooke T., Huard T.,
Terebey S., Audard M., Monin J.-L., Fukagawa M., Gudel M., Knapp G.R.,
Menard F., Allen L.E., Angione J.R., Baldovin-Saavedra C., Bouvier J.,
Briggs K., Dougados C., Evans N.J., Flagey N., Guieu S., Grosso N.,
Glauser A.M., Harvey P., Hines D., Latter W.B., Skinner S.L., Strom S.,
Tromp J., Wolf S.
<Astrophys. J. Suppl. Ser., 186, 259-307 (2010)>
=2010ApJS..186..259R 2010ApJS..186..259R
ADC_Keywords: Molecular clouds ; Photometry, infrared ; YSOs ;
Cross identifications
Keywords: circumstellar matter - infrared: stars - stars: formation -
stars: pre-main sequence
Abstract:
We report on the properties of pre-main-sequence objects in the Taurus
molecular clouds as observed in seven mid- and far-infrared bands with
the Spitzer Space Telescope. There are 215 previously identified
members of the Taurus star-forming region in our ∼44deg2 map; these
members exhibit a range of Spitzer colors that we take to define young
stars still surrounded by circumstellar dust (noting that ∼20% of the
bona fide Taurus members exhibit no detectable dust excesses). We
looked for new objects in the survey field with similar Spitzer
properties, aided by extensive optical, X-ray, and ultraviolet
imaging, and found 148 new candidate members of Taurus. We have
obtained follow-up spectroscopy for about half the candidate sample,
thus far confirming 34 new members, three probable new members, and 10
possible new members, an increase of 15%-20% in Taurus members. Of the
objects for which we have spectroscopy, seven are now confirmed
extragalactic objects, and one is a background Be star. The remaining
93 candidate objects await additional analysis and/or data to be
confirmed or rejected as Taurus members. Most of the new members are
Class II M stars and are located along the same cloud filaments as the
previously identified Taurus members. Among non-members with Spitzer
colors similar to young, dusty stars are evolved Be stars, planetary
nebulae, carbon stars, galaxies, and active galactic nuclei.
Description:
Padgett et al., 2008, http://irsa.ipac.caltech.edu/data/SPITZER/Taurus/
and 2010 (in preparation) present a comprehensive discussion of the
Spitzer data acquisition, reduction, and bandmerging to the 2MASS
data. In summary, we conducted the observations using Infrared Array
Camera (IRAC; 3.6, 4.5, 5.8, and 8um) and Multi-band Imaging
Photometer (MIPS for Spitzer; 24, 70, and 160um) in two epochs to
enable removal of asteroids from the final point-source catalog. The
observations were spread over three observing programs and three
years, 2005-2007.
We discussed merging the 2MASS and Spitzer data. We also need to match
our catalog to the other Taurus surveys (CFHT, SDSS, XEST survey -
Gudel et al. 2007, Cat. J/A+A/468/353).
We obtained follow-up spectroscopy for ∼75% of the candidate YSOs
discussed in this paper. Data were obtained over six runs between 2007
and 2009 at Keck and the Palomar 200". Most of the ≳200 spectra
are low-resolution optical, obtained with the Double Spectrograph at
Palomar (2008 November 30-December 3) or LRIS at Keck (2007 February).
Many spectra were taken in the IR with Triplespec at Palomar (2008
November 21-24 and 2008 December 21) or NIRSPEC at Keck (2007 December
and 2008 February). The IR spectra will be discussed in a forthcoming
paper; the optical spectra are discussed here.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table4.dat 181 215 Spitzer measurements for sample of previously
identified Taurus members
table5.dat 181 148 Spitzer measurements for sample of new candidate
Taurus members
table6.dat 105 215 Derived properties of previously identified Taurus
members
table7.dat 138 148 Derived properties of new potential Taurus members
table8.dat 73 143 List of new confirmed, probable, possible, and
pending Taurus members
table11.dat 243 134 *Individual miscellaneous non-YSO objects with
YSO-like colors
table12.dat 132 15 *Literature non-members regarded as potential new
members
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Note on table11.dat: These objects were selected at various points in our
selection process, but we have rejected these as YSOs. See associated text
for much more information.
Note on table12.dat: These objects were noted in the literature as likely
non-members, but we have promoted them to be candidate members based on our
Spitzer observations. See text for more information.
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See also:
II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)
J/ApJ/745/119 : Close companions to young stars. I. ChaI+Tau (Nguyen+, 2012)
J/ApJ/745/19 : Binary systems in Taurus-Auriga (Kraus+, 2012)
J/ApJS/196/4 : New young star candidates in Taurus-Auriga (Rebull+, 2011)
J/ApJ/720/480 : DISCS. I. Taurus protoplanetary disk data (Oberg+, 2010)
J/A+A/519/A83 : T Tau stars toward the Taurus-Auriga region (Takita+ 2010)
J/AJ/139/1338 : UV-selected stars in Tau and Upper Sco (Findeisen+, 2010)
J/ApJ/703/1964 : Spectra of three nearby star-forming regions (Furlan+, 2009)
J/PASJ/60/209 : Faint companions around YSOs in TMC (Itoh+, 2008)
J/ApJS/176/457 : Taurus dark cloud background star catalog (Shenoy+, 2008)
J/A+A/468/353 : XMM-Newton Extended Survey of Taurus (Guedel+, 2007)
J/AJ/132/2665 : QUEST2 BRI photometry of Taurus-Auriga PMS (Slesnick+, 2006)
J/ApJ/645/676 : Spatial distribution of BD* in Taurus (Luhman+, 2006)
J/ApJ/578/914 : Low-mass stars in Taurus (Hartmann, 2002)
J/ApJ/581/1194 : Taurus-Auriga PMS stars ages and Teff (Palla+, 2002)
J/A+AS/132/173 : New weak-line T Tauri stars in Taurus-Auriga (Li+ 1998)
J/A+AS/124/449 : Young stars south of Taurus-Auriga (Magazzu+ 1997)
J/A+A/312/439 : New T Tauri stars in Taurus-Auriga (Wichmann+, 1996)
J/ApJS/101/117 : UBVRIJHKLMNQ photometry in Taurus-Auriga (Kenyon+ 1995)
J/A+AS/101/485 : Multisite UBVRI photometry in Tau-Aur cloud (Bouvier+ 1993)
http://irsa.ipac.caltech.edu/data/SPITZER/Taurus/ : Spitzer Space Telescope
Survey of the Taurus region home page
Byte-by-byte Description of file: table[45].dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 15 A15 --- SST Spitzer Tau name (HHMMSS.s+DDMMSS; J2000)
17- 39 A23 --- CName Common name
41 A1 --- l_[3.6] Limit flag on [3.6]
42- 47 F6.2 mag [3.6] [6.6/16.3]? Spitzer/IRAC 3.6um band magnitude (1)
49- 52 F4.2 mag e_[3.6] ? Uncertainty in [3.6]
54 A1 --- l_[4.5] Limit flag on [4.5]
55- 60 F6.2 mag [4.5] [6.1/15.6]? Spitzer/IRAC 4.5um band magnitude (1)
62- 65 F4.2 mag e_[4.5] ? Uncertainty in [4.5]
67 A1 --- l_[5.8] Limit flag on [5.8]
69- 73 F5.2 mag [5.8] [3.4/14.7]? Spitzer/IRAC 5.8um band magnitude (1)
75- 78 F4.2 mag e_[5.8] ? Uncertainty in [5.8]
80 A1 --- l_[8.0] Limit flag on [8.0]
82- 86 F5.2 mag [8.0] [3.5/14.4]? Spitzer/IRAC 8.0um band magnitude (1)
88- 91 F4.2 mag e_[8.0] ? Uncertainty in [8]
93 A1 --- l_[24] Limit flag on [24]
94-100 F7.2 mag [24] [0.4/11.1]? Spitzer/MIPS 24um band magnitude (1)
102-105 F4.2 mag e_[24] ? Uncertainty in [24]
107 A1 --- l_[70] Limit flag on [70]
108-114 F7.2 mag [70] [-2.6/3.2]? Spitzer/MIPS 70um band magnitude (1)
116-119 F4.2 mag e_[70] ? Uncertainty in [70]
121 A1 --- l_[160] Limit flag on [160]
122-128 F7.2 mag [160] [-5.5/2.4]? Spitzer/MIPS 160um band magnitude (1)
130-133 F4.2 mag e_[160] ? Uncertainty in 160mag
135-143 A9 --- 24/70 Identification in 24/70 micron color-magnitude
diagram (no, yes or yes-faint)
145-153 A9 --- KS/24 Identification in Ks/70 micron
color-magnitude diagram (no, yes or yes-faint)
155-163 A9 --- 8/24 Identification in 8/24 micron color-magnitude
diagram (no, yes or yes-faint)
165-173 A9 --- 4.5/8 Identification in 4.5/8 micron color-magnitude
diagram (no, yes or yes-faint)
175-177 A3 --- IRAC Identification in IRAC color-color diagram (yes
or no)
179-181 A3 --- M1 [,b-i] Additional note(s) on measurements (2)
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Note (1): To convert between magnitudes and flux densities, we use
M=2.5log(F0/F) where the zero-point flux densities for the seven
Spitzer bands are 280.9, 179.7, 115.0, and 64.13Jy for IRAC and 7.14,
0.775, and 0.159Jy for MIPS.
Note (2): Note as follows:
b = MIPS-160 flux density for this object is subject to confusion with a
nearby source or sources.
c = MIPS-160 flux density for this object is compromised by missing and/or
saturated data.
d = MIPS-160 flux density for this object is hard saturated.
e = IRAC flux densities for 043835.4+261041=HV Tau C do not appear in our
automatically-extracted catalog. Flux densities here are those from
Hartmann et al. (2005ApJ...629..881H 2005ApJ...629..881H); since their observations have
more redundancy at IRAC bands, they are able to obtain reliable flux
densities for this object at IRAC bands. MIPS flux densities are
determined from our data.
f = The image morphology around 041426.2+280603 is complex; careful PSF
subtraction and modeling will be required to apportion flux densities
among the three local maxima seen in close proximity in the IRAC
images, which may or may not be three physically distinct sources.
g = Object previously identified in the literature as a potential YSO.
h = Object previously identified in the literature as a potential
non-member.
i = Object identified as a Taurus member by other authors using portions
of this Spitzer Legacy data set.
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Byte-by-byte Description of file: table6.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 15 A15 --- SST Spitzer Tau name (HHMMSS.s+DDMMSS; J2000)
17- 39 A23 --- CName Common name
41- 47 A7 --- c2dCat The c2d (Harvey+ 2007, Cat. J/ApJ/663/1149)
category (not yso, star or yso)
49- 56 A8 --- GutCat The Gutermuth+ (2008, Cat. J/ApJ/674/336)
category (class II, contam., embedded or star)
58- 61 A4 --- Class Our class (I, II, III or flat)
63- 74 A12 --- SpType MK Spectral type
76- 81 F6.1 0.1nm EW [-296/5.5]? Our Hα equivalent width
in units of Angstroms
83- 86 F4.1 mag AV [0/24]? The V band extinction
88- 91 F4.1 [Lsun] logL* [-2.9/2]? Star luminosity (G2)
93 A1 --- l_LIR/L Limit flag on LIR/L (G2)
95-101 E7.2 [-] LIR/L ? Ratio of IR to total luminosities
103-105 A3 --- M2 [ a-d,] Additional note(s) (3)
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Note (3): Note as follows:
a = Ca IR triplet in emission in our spectrum.
b = New spectral type, reported here.
c = Unreduced IR spectrum in-hand, to be discussed in a later paper.
d = 043552.7+225423=HP Tau AB was observed twice in the same night
(03 Dec 2008), and within 7 hrs the Hα equivalent width
changed from 1.95Å in absorption to 11.24Å in emission.
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Byte-by-byte Description of file: table7.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 15 A15 --- SST Spitzer Tau name (HHMMSS.s+DDMMSS; J2000)
17- 39 A23 --- CName Common name
41- 42 A2 --- Rank Our rank (A+ to C-) (G1)
44- 50 A7 --- c2dCat The c2d (Harvey+ 2007, Cat. J/ApJ/663/1149)
category
52- 59 A8 --- GutCat The Gutermuth+ (2008, Cat. J/ApJ/674/336)
category
61- 64 A4 --- Class Our class (I, II, III or flat)
66- 76 A11 --- SpType MK Spectral type
78- 83 F6.1 0.1nm EW [-489.1/11.5]? Our Hα equivalent width
in Angstrom units
85- 88 F4.1 mag AV [0/22.2]? The V band extinction
90- 93 F4.1 [Lsun] logL* [-2.4/2.1]? Star luminosity (G2)
95 A1 --- l_LIR/L Limit flag on LIR/L
97-103 E7.2 [-] LIR/L ? Ratio of IR to total luminosities (G2)
105-124 A20 --- Mmclass Adopted membership classification
126-138 A13 --- Note2 [ a-o,] Additional note(s) (4)
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Note (4): Note as follows:
a = Ca IR triplet in emission in our spectrum.
b = New spectral type, reported here.
c = Unreduced IR spectrum in-hand, to be discussed in a later paper.
d = Object previously identified in the literature as a potential
Taurus member.
e = Object previously identified in the literature as a
potential non-member.
f = Object identified as a Taurus member by other authors using portions
of this Spitzer Legacy data set.
g = X-ray source in the XEST survey.
h = Ultraviolet source in the XEST survey (optical monitor data).
i = Object found via X-rays in Scelsi et al. (2007A&A...468..405S 2007A&A...468..405S) and
confirmed as new member in Scelsi et al. (2008A&A...490..601S 2008A&A...490..601S); object
also independently rediscovered via IR excesses here.
j = High spatial-resolution optical images suggest IR flux density may be
subject to confusion with a nearby object.
k = Gravity analysis (see text) suggests intermediate gravity object and
therefore likely member.
l = UV excess source in SDSS data.
m = Extended emission seen in image at 8 micron or longer, which may be
affecting the long-wavelength photometry.
n = Object appears lower in the HR diagram than most Taurus members;
object may suffer from additional (unmodelled) extinction such as
may be found in edge-on disks, but may also be background giant.
o = Notes on specific objects:
* 041810.7+251957 = [GBM90] L1506 1 was observed in Jan and Dec 2008,
and the object went from 4.31Å in emission to 0.983Å in
absorption at Hα.
* 043621.4+271912: many emission lines in the blue spectrum, but not
in the red.
* 042350.1+264006=FS 116: appears in Hawarden et al. (2001MNRAS.325..563H 2001MNRAS.325..563H)
as a UKIRT JHK standard.
* 042215.6+265706=2MASS J04221568+2657060: has detected nebulosity in
Sloan images, which may be contributing to the measured flux density
at the longest Spitzer bands.
* 043249.3+225308 : within 6 arcsec of a known object (043249.1+225302).
* 041801.1+283526 : may be double source in CFHT image.
* 042920.8+274207 : shares many characteristics of young stars, but
also those of some post-main-sequence objects.
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Byte-by-byte Description of file: table8.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 A3 --- Mm Membership status (1)
5- 19 A15 --- SST SST Tau name (HHMMSS.s+DDMMSS; J2000)
21- 43 A23 --- CName Common name
45- 53 F9.6 deg RAdeg [62.998/72.424] Right ascension (J2000)
55- 63 F9.6 deg DEdeg [22.206/29.711] Declination (J2000)
65- 66 A2 --- Rank Our rank (A+ to C-) (G1)
68- 73 F6.2 arcmin Dist [0.11/120.82] Distance (2)
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Note (1): Membership code as follows:
M = New members
PrM = Probable new members
PoM = Possible new members
AM = Needs additional follow-up (beyond the spectra we have)
pM = Pending (spectroscopic) follow up
Note (2): Angular distance to nearest previously identified Taurus member.
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Byte-by-byte Description of file: table11.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 A3 --- Class Object type (1)
5- 19 A15 --- SST SST Tau name (HHMMSS.s+DDMMSS; J2000)
21- 61 A41 --- OName Other name(s)
63-243 A181 --- Notes Notes
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Note (1): Class code as follows:
PN = Planetary nebulae
CS = Carbon star
BGl = Background giants from the literature
BGb = Background giants based on brightness
IE = Insignificant IR excess
8um = 8µ pop-ups
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Byte-by-byte Description of file: table12.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 15 A15 --- SST SST Tau name (HHMMSS.s+DDMMSS; J2000)
17- 39 A23 --- OName Other name
41-132 A92 --- Notes Notes
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Global notes:
Note (G1): Out of the 148 new candidate Taurus members, according to the
letter grades we assigned (see Section 3.1.4), there are 50 with
letter "A+", "A", or "A-" (most believable), 66 with grade "B+", "B",
or "B-", and 25 with grade "C+", "C", or "C-" (least believable).
These grades incorporate all the available photometric and
spectroscopic information for each object; the remaining seven do not
have grades because they are galaxies based on the follow-up spectroscopy.
Note (G2): L* is an estimate of the star's luminosity and LIR/Ltot is an
estimate of the ratio of the IR excess luminosity to the star's total
(photospheric+IR) luminosity (where Ltot = L* + LIR). See section 3.3
for further explanations.
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 01-Oct-2013