J/ApJ/746/23 Radio observations of ultracool dwarf stars (McLean+, 2012)
The radio activity-rotation relation of ultracool dwarfs.
McLean M., Berger E., Reiners A.
<Astrophys. J., 746, 23 (2012)>
=2012ApJ...746...23M 2012ApJ...746...23M
ADC_Keywords: Stars, late-type ; Radio continuum ; Photometry, infrared ;
Rotational velocities ; Spectral types
Keywords: brown dwarfs - radio continuum: stars - stars: activity -
stars: low-mass - stars: magnetic field
Abstract:
We present a new radio survey of about 100 late-M and L dwarfs
undertaken with the Very Large Array. The sample was chosen to explore
the role of rotation in the radio activity of ultracool dwarfs. As
part of the survey we discovered radio emission from three new
objects, 2MASS J0518113-310153 (M6.5), 2MASS J0952219-192431 (M7), and
2MASS J1314203+132001 (M7), and made an additional detection of
LP 349-25 (M8). Combining the new sample with results from our
previous studies and from the literature, we compile the largest
sample to date of ultracool dwarfs with radio observations and
measured rotation velocities.
Description:
We carried out a survey of 104 M and L dwarfs with the Very Large
Array (VLA). The targets are concentrated in the spectral type range
M6-M9, where the X-ray/radio correlation and the X-ray/Hα
activity-rotation relation break down. The sample includes sources
with no previous radio observations, as well as several objects with
previous detections or upper limits. The majority of the sample is
located at ≲20pc. Each object was observed for a single contiguous
hour at 8.46 GHz.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 91 102 Results from our radio survey of M and L dwarfs
table2.dat 94 155 Results from the literature
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See also:
J/A+A/549/A131 : Radio survey of ultracool dwarfs (Antonova+, 2013)
J/MNRAS/404/1817 : 2MASS/SDSS data for 806 ultracool dwarfs (Zhang+, 2010)
J/ApJ/701/1922 : Radio interferometric planet search. I. (Bower+, 2009)
J/ApJ/704/975 : Rotational velocities for M dwarfs (Jenkins+, 2009)
J/AJ/137/1 : PMs and astrometry of late-type dwarfs (Faherty+, 2009)
J/AJ/136/1290 : Ultracool dwarfs from the 2MASS (Reid+, 2008)
J/ApJ/676/1281 : L and T dwarfs in 2MASS/SDSS (Metchev+, 2008)
J/AJ/133/2258 : Activity and kinematics of ultracool dwarfs (Schmidt+, 2007)
J/ApJ/648/629 : Radio observations of late M, L, and T dwarfs (Berger+, 2006)
J/AJ/132/891 : Binaries among nearby L dwarfs (Reid+, 2006)
J/A+A/446/515 : Distances of nearby ultracool dwarfs (Phan-Bao+, 2006)
J/PASP/118/659 : RI photometry of 2MASS late M and L dwarfs (Liebert+, 2006)
J/other/ARA+A/43.195 : L and T dwarf stars (Kirkpatrick, 2005)
J/AJ/127/3553 : JHK photometry & spectroscopy for L & T dwarfs (Knapp+, 2004)
J/AJ/126/1526 : IR photometry of ultracool dwarfs (Bouy+, 2003)
J/AJ/126/2421 : 2MASS-Selected sample of ultracool dwarfs (Cruz+, 2003)
J/A+A/331/581 : Rotation and activity in field M dwarfs (Delfosse+ 1998)
Byte-by-byte Description of file: table[12].dat
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Bytes Format Units Label Explanations
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1- 14 A14 --- 2MASS 2MASS identification (HHMMSSs+DDMMSS; J2000)
15- 16 A2 --- m_2MASS [AB ] 2MASS component
18- 29 A12 --- OName Other name
31- 34 A4 --- SpT MK spectral type
36- 40 F5.2 mag Jmag ? 2MASS J-band magnitude
42- 46 F5.2 mag Ksmag ? 2MASS Ks-band magnitude
48- 50 I3 pc Dist ? Heliocentric distance (1)
52 A1 --- l_vsini Limit flag on vsini
54- 57 F4.1 km/s vsini ? Projected rotation velocity (2)
59- 63 F5.2 [Lsun] Lbol [-5.8,-1.1]? Bolometric luminosity (log scale)
65 A1 --- l_LHa/bol Limit flag on LHa/bol
67- 71 F5.2 [-] LHa/bol [-8.18,-3.18]? Hα activity (3)
73 A1 --- l_Fr Limit flag on Fr
75- 79 I5 uJy Fr Radio flux density (8.46GHz or 5GHz if in Ref)
81- 83 I3 uJy e_Fr ? Fr uncertainty
85 A1 --- l_Lr/bol Limit flag on Lr/bol
87- 91 F5.2 [-] Lr/bol [-9.8,-4.1] Ratio of radio to bolometric
luminosity
93- 94 I2 --- Ref [1,13]? Reference for radio flux density
measurements (only for table 2) (4)
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Note (1): Distance from parallax or photometric estimate (from SIMBAD;
Faherty et al. 2009, Cat. J/AJ/137/1; Cruz et al. 2003,
Cat. J/AJ/126/2421)
Note (2): Projected rotation velocity (from Mohanty & Basri 2003ApJ...583..451M 2003ApJ...583..451M;
Reid et al. 2002AJ....124..519R 2002AJ....124..519R; Reiners & Basri 2008ApJ...684.1390R 2008ApJ...684.1390R,
2010ApJ...710..924R 2010ApJ...710..924R; Jenkins et al. 2009, Cat. J/ApJ/704/975)
Note (3): Hα activity (from Delfosse et al. 1998, Cat. J/A+A/331/581;
Mohanty & Basri 2003ApJ...583..451M 2003ApJ...583..451M; Reiners & Basri
2008ApJ...684.1390R 2008ApJ...684.1390R, 2010ApJ...710..924R 2010ApJ...710..924R)
Note (4): Reference as follows:
1 = Guedel et al. 1993ApJ...415..236G 1993ApJ...415..236G;
2 = White et al. 1989ApJS...71..895W 1989ApJS...71..895W (5GHz);
3 = Willson et al. 1988A&A...199..255W 1988A&A...199..255W (5GHz);
4 = Bower et al. 2009, Cat. J/ApJ/701/1922 (5GHz);
5 = Jackson et al. 1989A&A...210..284J 1989A&A...210..284J;
6 = Berger 2006, Cat. J/ApJ/648/629;
7 = Caillault et al. 1988AJ.....95..887C 1988AJ.....95..887C (5GHz);
8 = Burgasser & Putman 2005ApJ...626..486B 2005ApJ...626..486B;
9 = Krishnamurthi et al. 1999AJ....118.1369K 1999AJ....118.1369K;
10 = Berger 2002ApJ...572..503B 2002ApJ...572..503B;
11 = Phan-Bao et al. 2007ApJ...658..553P 2007ApJ...658..553P;
12 = Berger et al. 2001Natur.410..338B 2001Natur.410..338B;
13 = Berger et al. 2009ApJ...695..310B 2009ApJ...695..310B
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History:
From electronic version of the journal
(End) Emmanuelle Perret [CDS] 05-Aug-2013