2014ApJ...780....7P

Query : 2014ApJ...780....7P

2014ApJ...780....7P - Astrophys. J., 780, 7 (2014/January-1)

Hypervelocity star candidates in the SEGUE G and K dwarf sample.

PALLADINO L.E., SCHLESINGER K.J., HOLLEY-BOCKELMANN K., ALLENDE PRIETO C., BEERS T.C., LEE Y.S. and SCHNEIDER D.P.

Abstract (from CDS):

We present 20 candidate hypervelocity stars from the Sloan Extension for Galactic Understanding and Exploration (SEGUE) G and K dwarf samples. Previous searches for hypervelocity stars have only focused on large radial velocities; in this study, we also use proper motions to select the candidates. We determine the hypervelocity likelihood of each candidate by means of Monte Carlo simulations, considering the significant errors often associated with high proper motion stars. We find that nearly half of the candidates exceed their escape velocities with at least 98% probability. Every candidate also has less than a 25% chance of being a high-velocity fluke within the SEGUE sample. Based on orbits calculated using the observed six-dimensional positions and velocities, few, if any, of these candidates originate from the Galactic center. If these candidates are truly hypervelocity stars, they were not ejected by interactions with the Milky Way's supermassive black hole. This calls for a more serious examination of alternative hypervelocity-star ejection scenarios.

Abstract Copyright: ∼

Journal keyword(s): galaxies: kinematics and dynamics - Galaxy: halo - Galaxy: stellar content - Local Group

Nomenclature: Table 1: [PSH2014] HVS NN (Nos 1-20).

Errata: erratum vol. 782, art. 57 (2014)

Simbad objects: 27

Full paper

View the references in ADS

Number of rows : 27

N	Identifier	Otype	ICRS (J2000) RA	ICRS (J2000) DEC	Mag U	Mag B	Mag V	Sp type	#ref 1850 - 2023	#notes
1	M 31	G	00 42 44.330	+41 16 07.50	4.86	4.36	3.44	~	12388	1
2	SDSS J011933.45+384913.0	HV*	01 19 33.4616166456	+38 49 13.093223700				~	2	0
3	SDSS J023433.42+262327.5	*	02 34 33.4210550232	+26 23 27.585274488				~	1	0
4	SDSS J025450.18+333158.4	HV*	02 54 50.1882506112	+33 31 58.421834616				K2V	3	0
5	NAME Magellanic Clouds	GrG	03 00	-71.0				~	6834	1
6	SDSS J035429.27-061354.1	HV*	03 54 29.2766934552	-06 13 54.158645784				G9V	3	0
7	SDSS J060306.77+825829.2	HV*	06 03 06.7771324536	+82 58 29.192234484				~	2	0
8	[PSH2014] HVS 17	HV*	06 42 57.0264618192	+37 16 04.371806496				~	3	0
9	[PSH2014] HVS 7	HV*	06 43 37.1326353240	+29 14 10.073927328				~	3	0
10	SDSS J073542.35+164941.4	HV*	07 35 42.3577096560	+16 49 41.512596060				~	2	0
11	SDSS J074728.84+185520.4	HV*	07 47 28.8508282512	+18 55 20.519590332				~	2	0
12	[PSH2014] HVS 15	PM*	09 58 16.4001677808	+00 52 24.396784176				~	2	0
13	SDSS J110815.19-155210.3	*	11 08 15.1933986720	-15 52 10.401680712				~	1	0
14	[PSH2014] HVS 4	PM*	11 31 02.8804183224	+66 57 51.177843756				~	2	0
15	NAME NGP	reg	12 51 26.275	+27 07 41.70				~	1148	0
16	[PSH2014] HVS 13	*	13 44 27.8055204744	+28 25 02.725734612				~	2	0
17	SDSS J145132.12+003258.0	HV*	14 51 32.1204354072	+00 32 58.016746788				~	2	0
18	SDSS J160620.65+042451.5	*	16 06 20.6595905472	+04 24 51.614864172				~	1	0
19	SDSS J165956.02+392414.9	*	16 59 56.0324493144	+39 24 14.959019340				~	1	0
20	SDSS J172630.60+075544.1	HV*	17 26 30.6063952224	+07 55 44.046919812				~	2	0
21	NAME Galactic Center	reg	17 45 39.60213	-29 00 22.0000				~	13907	0
22	NAME Sgr A*	X	17 45 40.03599	-29 00 28.1699				~	4222	3
23	SDSS J185018.09+191236.1	*	18 50 18.0901658544	+19 12 36.157582512				~	1	0
24	SDSS J202446.41+121813.4	*	20 24 46.4151228168	+12 18 13.450477068				~	1	0
25	SDSS J225912.13+074356.5	HV*	22 59 12.1307403672	+07 43 56.562234744				~	2	0
26	NAME Galactic Bulge	reg	~	~				~	4173	0
27	NAME Local Group	GrG	~	~				~	8155	0

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