J/ApJ/867/L8 Gaia kinematic data of runaway & field OB stars in SMC (Oey+, 2018)
Resolved kinematics of runaway and field OB stars in the Small Magellanic Cloud.
Oey M.S., Jones J.D., Castro N., Zivick P., Besla G., Januszewski H.C.,
Moe M., Kallivayalil N., Lennon D.J.
<Astrophys. J., 867, L8 (2018)>
=2018ApJ...867L...8O 2018ApJ...867L...8O
ADC_Keywords: Stars, OB; Magellanic Clouds; Radial velocities;
Binaries, spectroscopic
Keywords: binaries: general; galaxies: star clusters: general;
Magellanic Clouds; stars: kinematics and dynamics; stars: massive;
X-rays: binaries
Abstract:
We use Gaia Data Release 2 proper motions of field OB stars from the
Runaways and Isolated O-Type Star Spectroscopic Survey of the Small
Magellanic Cloud (SMC) to study the kinematics of runaway stars. The
data reveal that the SMC Wing has a systemic peculiar motion relative
to the SMC Bar of (vα,vδ)=(62±7,-18±5)km/s and
relative radial velocity +4.5±5.0km/s. This unambiguously
demonstrates that these two regions are kinematically distinct: the
Wing is moving away from the Bar, and towards the Large Magellanic
Cloud with a 3D velocity of 64±10km/s. This is consistent with
models for a recent, direct collision between the Clouds. We present
transverse velocity distributions for our field OB stars, confirming
that unbound runaways comprise on the order of half our sample,
possibly more. Using eclipsing binaries and double-lined spectroscopic
binaries as tracers of dynamically ejected runaways, and high-mass
X-ray binaries (HMXBs) as tracers of runaways accelerated by supernova
kicks, we find significant contributions from both populations. The
data suggest that HMXBs have lower velocity dispersion relative to
dynamically ejected binaries, consistent with the former group
corresponding to less energetic supernova kicks that failed to unbind
the components. Evidence suggests that our fast runaways are dominated
by dynamical, rather than supernova, ejections.
Description:
The catalogue contains kinematic parameters of 315 field OB stars from
the Runaways and Isolated O-Type Star Spectroscopic Survey of the SMC
(RIOTS4; Lamb+ 2016, J/ApJ/817/113) identified in the Gaia DR2 (I/345)
catalog by specifying a position match within 3" and magnitude match
|G-V|<0.3 (yielding 328 matches). The sample is further vetted by
including only stars having both RA and DEC PM errors <1σ from
the median error, eliminating 12 stars, and by deleting one more star
that has RA or DEC errors >3.5σ after the initial clip.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 75 315 *Kinematic data for RIOTS4 field OB stars
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Note on table1.dat: Our study is based on the Runaways and Isolated O-Type Star
Spectroscopic Survey of the SMC (RIOTS4), which is yielding a
detailed, quantitative characterization of the SMC field OB population
(e.g. Lamb+ 2016, J/ApJ/817/113).
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See also:
II/236 : UBVR CCD survey of the Magellanic clouds (Massey+, 2002)
I/345 : Gaia DR2 (Gaia Collaboration, 2018)
J/A+A/331/949 : Wolf-Rayet and O-star runaways kinematics (Moffat+ 1998)
J/AJ/127/1632 : UBVR(UIT) photometry of O and OB stars in SMC (Oey+, 2004)
J/AJ/137/3358 : Speckle interferometry of massive stars (Mason+, 2009)
J/other/Sci/337.444 : RV curves of Galactic massive O stars (Sana+, 2012)
J/MNRAS/442/1663 : Velocities of red giants in the SMC (Dobbie+, 2014)
J/ApJ/810/61 : Early-type EBs with intermediate periods (Moe+, 2015)
J/A+A/586/A81 : High-mass X-ray binaries in the SMC (Haberl+, 2016)
J/ApJ/817/113 : RIOTS4: spec. survey of SMC field OB stars (Lamb+, 2016)
J/AcA/66/421 : Eclipsing binaries in the Magellanic System (Pawlak+, 2016)
J/MNRAS/472/3887 : Kinematic data for stars in OB-associations (Melnik+, 2017)
J/AJ/156/98 : Runaway stars in 30 Doradus region of LMC (Platais+, 2018)
J/ApJ/868/57 : HR diagram of OB stars in the SMC (Castro+, 2018)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 5 I5 --- ID [107/84544] ID from Massey 2002, II/236 ;
<[M2002] SMC NNNNNN> in Simbad
7- 15 A9 --- Group Subgroup types (1)
17- 22 F6.2 km/s trVel [2/287]? Transverse residual velocity (2)
24- 29 F6.2 km/s ltrVel [2/295]? Transverse residual local velocity (2)
31- 35 A5 --- Qual Flags for asymmetry and crowding (3)
37- 42 F6.2 km/s RVel [-90/242]? Residual radial velocity (2)
44- 46 I3 km/s vRA [-41/523] RA velocity (4)
48- 49 I2 km/s e_vRA [9/40] Error in vRA (5)
51- 54 I4 km/s vDE [-493/-204] Dec velocity (4)
56- 57 I2 km/s e_vDE [7/29] Error vDec (5)
59- 61 I3 km/s lVelRA [166/415] RA local velocity (4)
63- 64 I2 km/s e_lVelRA [2/24] Error in vloc-RA (5)
66- 69 I4 km/s lVelDE [-425/-325] Dec local velocity (4)
71- 75 I5 km/s e_lVelDE [1/16] Error in vloc-Dec (5)
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Note (1): 'E', 'S', 'H' indicate EB (eclipsing binary), SB2 (double-lined
spectroscopic binary), and HMXB (high-mass X-ray binaries),
respectively; 'B', 'W', 'D' indicate Bar, Wing, and boundary stars,
respectively; 'm' indicates object in multi-epoch spectroscopic sample.
Note (2): Residual velocity relative to SMC and Wing systemic motion, including
geometric correction. The vloc,trans values are computed relative to
local velocity fields (see Section 3.2). RV errors are typically 10km/s.
Note (3): 'a' indicates a difference in RA vs Dec fitted gaussian PSF >0.3pix,
where typical PSF is 3pix. The second and third values give the number
of stars within 1 arcsec and 1.5 arcsec, respectively.
Note (4): RA and Dec velocities, and local RA and Dec velocities, computed from
GAIA proper motions, without geometric or systematic velocity
corrections.
Note (5): GAIA measurement errors, not including systematic errors (see text).
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 21-Oct-2019