J/ApJ/813/26 Runaway M dwarf candidates from SDSS-DR7 (Favia+, 2015)
Runaway M dwarf candidates from the Sloan Digital Sky Survey.
Favia A., West A.A., Theissen C.A.
<Astrophys. J., 813, 26 (2015)>
=2015ApJ...813...26F 2015ApJ...813...26F (SIMBAD/NED BibCode)
ADC_Keywords: Proper motions ; Stars, M-type ; Spectral types ;
Stars, distances ; Radial velocities
Keywords: brown dwarfs; proper motions; stars: kinematics and dynamics;
stars: late-type; stars: low-mass
Abstract:
We present a sample of 20 runaway M dwarf candidates (RdMs) within
1kpc of the Sun whose Galactocentric (GC) velocities exceed 400km/s.
The candidates were selected from the Sloan Digital Sky Survey (SDSS)
DR7 M Dwarf Catalog of West et al. (2011, J/AJ/141/97). Our RdMs have
SDSS+USNO-B proper motions that are consistent with those recorded in
the PPMXL, LSPM, and combined Wide-field Infrared Survey
Explorer+SDSS+Two-micron All-sky Survey catalogs. Sixteen RdMs are
classified as dwarfs, while the remaining four RdMs are subdwarfs. We
model the Galactic potential using a bulge-disk-halo profile. Our
fastest RdM, with a GC velocity of 658.5±236.9km/s, is a possible
hypervelocity candidate, as it is unbound in 77% of our simulations.
About half of our RdMs have kinematics that are consistent with
ejection from the Galactic center. Seven of our RdMs have kinematics
consistent with an ejection scenario from M31 or M32 to within
2σ, although our distance-limited survey makes such a
realization unlikely. No more than four of our RdMs may have
originated from the Leo stream. We propose that to within measurement
errors, most of our bound RdMs are likely disk runaways or halo
objects, and may have been accelerated through a series of multi-body
interactions within the Galactic disk or possibly supernovae
explosions.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table3.dat 133 20 Proper motions for our runaway M dwarf candidates
table4.dat 129 20 Properties of our runaway M dwarf candidates
table6.dat 84 20 Galactic potential test results for our runaway
M dwarf candidates
table9.dat 69 20 Runaway M dwarf (RdM) velocity angles and
position angles of M31 and Leo Stream
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See also:
I/317 : The PPMXL Catalog (Roeser+ 2010)
II/294 : The SDSS Photometric Catalog, Release 7 (Adelman-McCarthy+, 2009)
I/298 : LSPM-North Catalog (Lepine+ 2005)
II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)
J/AJ/151/41 : MoVeRS Catalog Schema (Theissen+, 2016)
J/AJ/150/77 : Catalog of hypervelocity candidate stars (Vickers+, 2015)
J/ApJ/794/146 : M dwarfs with IR excess (Theissen+, 2014)
J/AJ/144/93 : Close white dwarf + M dwarf binaries (WD+dM) (Morgan+, 2012)
J/ApJ/751/55 : MMT hypervelocity star survey. II. (Brown+, 2012)
J/AJ/143/67 : SLoWPoKES. II. Wide, low-mass binaries (Dhital+, 2012)
J/AJ/141/97 : SDSS DR7 M dwarfs (West+, 2011)
J/PASP/121/117 : Fe & Ti abund. of 12 low-metallicity M stars (Woolf+, 2009)
J/AJ/135/785 : SDSS-DR5 low-mass star spectroscopic sample (West+, 2008)
J/ApJ/671/1708 : Hypervelocity stars. III (Brown+, 2007)
J/AJ/134/2398 : Stellar SEDs in SDSS and 2MASS filters (Covey+, 2007)
J/ApJ/660/311 : Hypervelocity stars. II. (Brown+, 2007)
J/ApJ/647/303 : Spectroscopic survey of hypervelocity stars (Brown+, 2006)
J/AJ/131/582 : Cool white dwarfs in the SDSS (Kilic+, 2006)
http://www.sdss3.org/ : SDSS-III home page
Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 2 I2 --- Seq Runaway M dwarf running number (RdM)
4- 22 A19 --- SDSS SDSS IAU positional format (JHHMMSS.ss+DDMMSS.s)
24 A1 --- f_SDSS [s] s: extreme subdwarf (see section 3.1);
column added by CDS
26- 33 F8.4 deg RAdeg Right Ascension in decimal degrees (J2000)
35- 43 F9.5 deg DEdeg Declination in decimal degrees (J2000)
45- 50 F6.1 mas/yr pmRA1 [-517/454] Proper Motion in RA,
µα from SDSS+USNO-B (1)
52- 54 F3.1 mas/yr e_pmRA1 [5/7] Uncertainty in pmRA1, µα (1)
56- 61 F6.1 mas/yr pmDE1 [-448/139] Proper Motion in DEC,
µδ from SDSS+USNO-B (1)
63- 65 F3.1 mas/yr e_pmDE1 [5/7] Uncertainty in pmDE1, µδ (1)
67- 72 F6.1 mas/yr pmRA2 [-519/450] Proper Motion in RA,
µα from PPMXL (2)
74- 76 F3.1 mas/yr e_pmRA2 [7.2] Uncertainty in pmRA2, µα (2)
78- 83 F6.1 mas/yr pmDE2 [-447/137] Proper Motion in DEC,
µδ from PPMXL (2)
85- 87 F3.1 mas/yr e_pmDE2 [7.2] Uncertainty in pmDE2, µδ (2)
89- 94 F6.1 mas/yr pmRA3 [-525/458] Proper Motion in RA,
µα from WISE+SDSS+2MASS (3)
96-100 F5.1 mas/yr e_pmRA3 [13/138] Uncertainty in pmRA3, µα (3)
102-107 F6.1 mas/yr pmDE3 [-443/159] Proper Motion in DEC,
µδ from WISE+SDSS+2MASS (3)
109-113 F5.1 mas/yr e_pmDE3 [15/140] Uncertainty in pmDE3, µδ (3)
115-118 I4 mas/yr pmRA4 [-525/457]? Proper Motion in RA,
µα from LSPM (4)
120-123 F4.1 mas/yr e_pmRA4 [14.6]? Uncertainty in pmRA4, µα (4)
125-128 I4 mas/yr pmDE4 [-430/143]? Proper Motion in DEC,
µδ from LSPM (4)
130-133 F4.1 mas/yr e_pmDE4 [12.6]? Uncertainty in pmDE4, µδ (4)
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Note (1): SDSS+USNO-B catalog; Munn et al. (2004AJ....127.3034M 2004AJ....127.3034M;
2008AJ....136..895M 2008AJ....136..895M)
Note (2): PPMXL catalog; Roeser et al. (2010, I/317)
Note (3): WISE+SDSS+2MASS catalog; Theissen et al. (2016, J/AJ/151/41)
Note (4): LSPM catalog; Lepine (2005, J/AJ/130/1680)
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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- 2 I2 --- Seq Runaway M dwarf running number (RdM)
4- 22 A19 --- SDSS SDSS IAU positional format (JHHMMSS.ss+DDMMSS.s)
24- 24 I1 --- SpT [0/1] M-type spectral subtype
26- 29 F4.2 --- zeta [0.2/4.2] Metallicity-dependent parameter,
ζ (5)
31- 35 F5.2 --- e_zeta [0.06/12] Uncertainty in ζ (5)
37- 41 F5.2 mag rmag [16.2/18.1] SDSS r-band PSF,
extinction-corrected magnitude (6)
43- 46 F4.2 mag e_rmag Uncertainty in rmag (6)
48- 50 I3 pc Dist [232/954] Distance
52- 54 I3 pc e_Dist Uncertainty in Dist
56- 61 F6.1 km/s HRV [-318/185] Heliocentric radial velocity
63- 66 F4.1 km/s e_HRV Uncertainty in HRV
68- 73 F6.1 km/s U [-534/646] Velocity toward Galactic center (7)
75- 79 F5.1 km/s e_U Uncertainty in U
81- 86 F6.1 km/s V [-724/150] Velocity toward Galactic rotation (7)
88- 92 F5.1 km/s e_V Uncertainty in V
94- 99 F6.1 km/s W [-244/166] Velocity toward North Galactic Pole (7)
101-105 F5.1 km/s e_W Uncertainty in W
107-111 F5.1 km/s TV [200/779] Tangential velocity (proper motion
scaled to distance)
113-117 F5.1 km/s e_TV Uncertainty in TV
119-123 F5.1 km/s Vtot [400/659] Velocity of the star with respect to
the Galactic center
125-129 F5.1 km/s e_Vtot Uncertainty in Vtot
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Note (5): ζ as defined in Lepine et al. (2007ApJ...669.1235L 2007ApJ...669.1235L)
where subdwarfs, extreme subdwarfs, and ultra subdwarfs, for ζ
in the ranges 0.5-0.825, 0.2-0.5, and less than 0.2, respectively.
Note (6): Extinction-corrected using the method of Jones et al.
(2011AJ....142...44J 2011AJ....142...44J) or Schlegel et al. (1998ApJ...500..525S 1998ApJ...500..525S)
if the Runaway M dwarf (RdM) was not in the Jones et al.
(2011AJ....142...44J 2011AJ....142...44J) catalog.
Note (7): Adopted 250km/s for the velocity of the Local Standard of Rest and
a peculiar velocity of the Sun relative to the LSR as
(U,V,W)=(11.1,12.24,7.25).
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Byte-by-byte Description of file: table6.dat
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Bytes Format Units Label Explanations
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1- 2 I2 --- Seq Runaway M dwarf running number (RdM)
4- 22 A19 --- SDSS SDSS IAU positional format (JHHMMSS.ss+DDMMSS.s)
24- 29 F6.1 km/s U [-534/646] Velocity toward Galactic center
31- 35 F5.1 km/s e_U Uncertainty in U
37- 42 F6.1 km/s V [-724/150] Velocity toward Galactic rotation
44- 48 F5.1 km/s e_V Uncertainty in V
50- 55 F6.1 km/s W [-244/166] Velocity toward North Galactic Pole
57- 61 F5.1 km/s e_W Uncertainty in W
63- 65 A3 --- Rvir? [yes/no ] Is unbound if RdM reaches Rvir
within 2.5Gyr
67- 72 F6.1 Myr tesc [628/1369]? Escape time for unbound RdMs (8)
74- 78 F5.1 kpc Rmax [36.7/174]? Rmax for bound RdMs (8)
81- 84 F4.1 --- Unbd [0/77.2] Percentage of unbound simulations (9)
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Note (8): The escape time, tesc, is reported for unbound Runaway M dwarfs
(RdMs), whereas the maximum distance, Rmax, is reported for bound
RdMs. See Section 3.2.
Note (9): Represents the percentage of our simulations (see Section 3.3)
in which the Runaway M dwarf (RdM) reaches Rmax.
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Byte-by-byte Description of file: table9.dat
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Bytes Format Units Label Explanations
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1- 2 I2 --- Seq Runaway M dwarf running number (RdM)
4- 22 A19 --- SDSS SDSS IAU positional format (JHHMMSS.ss+DDMMSS.s)
24- 28 F5.1 deg b Galactic latitude of the velocity angle
30- 33 F4.1 deg e_b 2σ uncertainty in b
35- 39 F5.1 deg l Galactic longitude of the velocity angle
41- 45 F5.1 deg e_l 2σ uncertainty in l
47- 51 F5.1 deg dpsi-M31 [38/148] Velocity Angle relative to M31 (10)
53- 57 F5.1 deg e_dpsi-M31 2σ uncertainty in dpsi-M31
59- 63 F5.1 deg dpsi-Leo [44/116] Velocity Angle relative to Leo (11)
65- 69 F5.1 deg e_dpsi-Leo 2σ uncertainty in dpsi-Leo
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Note (10): M31 is located at b=-21.573deg, l=121.174 deg
Note (11): The Leo stream is located at approximately b=+60deg, l=230deg
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 11-Feb-2016