J/AJ/167/21 Photometry of stars within 3.2' from BH 261 (Kunder+, 2024)
The Milky Way Bulge Extra-tidal Star Survey: BH 261 (AL 3).
Kunder A., Prudil Z., Covey K.R., Hughes J., Joyce M., Simion I.T.,
Kuss R., Campos C., Johnson C.I., Pilachowski C.A., Larson K.A.,
Koch-Hansen A.J., Marchetti T., Rich M.R., Butler E., Clarkson W.I.,
Rivet M., Devine K., Vivas A.K., Perren G.I., Soto M., Silva E.
<Astron. J., 167, 21 (2024)>
=2024AJ....167...21K 2024AJ....167...21K
ADC_Keywords: Milky Way; Clusters, globular; Photometry, ugriz;
Spectra, optical ; Radial velocities
Keywords: Stellar populations ; Galactic archaeology ; Milky Way dynamics
; Galactic bulge ; Galaxy bulges ; Globular star clusters ;
Stellar accretion
Abstract:
The Milky Way Bulge extra-tidal star survey is a spectroscopic survey
with the goal of identifying stripped globular cluster stars from
inner Galaxy clusters. In this way, an indication of the fraction of
metal-poor bulge stars that originated from globular clusters can be
determined. We observed and analyzed stars in and around BH261, an
understudied globular cluster in the bulge. From seven giants within
the tidal radius of the cluster, we measured an average heliocentric
radial velocity of RV=-61±2.6km/s with a radial velocity
dispersion of σ=6.1±1.9km/s. The large velocity dispersion
may have arisen from tidal heating in the cluster's orbit about the
Galactic center, or because BH261 has a high dynamical mass as well as
a high mass-to-light ratio. From spectra of five giants, we measure an
average metallicity of [Fe/H]=-1.1±0.2dex. We also
spectroscopically confirm an RR Lyrae star in BH 261, which yields a
distance to the cluster of 7.1±0.4kpc. Stars with 3D velocities
and metallicities consistent with BH261 reaching to ∼0.5deg from the
cluster are identified. A handful of these stars are also consistent
with the spatial distribution of potential debris from models focusing
on the most recent disruption of the cluster.
Description:
New spectra were collected using the AAOmega multifibre spectrograph
at the 3.9m Anglo-Australian Telescope (AAT, Siding Spring
Observatory, Coonabarabran, NSW, Australia). The five-night run
occurred on 2022 July 20-24 (PROP-ID: O/2022A/3002).
Radial velocities were measured using IRAF's xcsao routine, which
utilizes cross-correlation against another spectrum. The three spectra
we used as cross-correlation templates were stars observed during the
same run, selected from the Apache Point Observatory Galaxy Evolution
Experiment (APOGEE) database.
Objects:
------------------------------------------------------
RA (ICRS) DE Designation(s)
------------------------------------------------------
18 14 06.60 -28 38 06.0 Cl VDBH 261 = [AL67] Cl* 3
------------------------------------------------------
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 97 10518 Blanco DECam Bulge Survey (BDBS) photometry of stars
within 3.2' from BH 261
table2.dat 96 12 Positions, Gaia proper motions, radial velocities
and [Fe/H] metallicities of the probable member
stars of BH 261
table3.dat 89 19 Positions, Gaia proper motions, radial velocities
and spectroscopic [Fe/H] metallicities of the
candidate extra-tidal stars stripped from BH 261
--------------------------------------------------------------------------------
See also:
I/337 : Gaia DR1 (Gaia Collaboration, 2016)
III/279 : RAVE 5th data release (Kunder+, 2017)
I/350 : Gaia EDR3 (Gaia Collaboration, 2020)
VII/195 : Globular Clusters in the Milky Way (Harris, 1996)
VII/202 : Globular Clusters in the Milky Way (Harris, 1997)
J/MNRAS/364/179 : BVI photometry of 8 open clusters (Carraro+, 2005)
J/ApJS/197/29 : Chemical compositions of 11 RR Lyrae (For+, 2011)
J/A+A/534/A136 : Halo red giants from the SEGUE survey (Martell+, 2011)
J/A+A/540/A27 : Spectroscopy in Galactic globular clusters (Saviane+, 2012)
J/A+A/549/A147 : Abund of microlensed bulge dwarf stars. V. (Bensby+, 2013)
J/ApJ/809/59 : Ophiuchus stellar stream with PS1 data (Sesar+, 2015)
J/A+A/587/A2 : SP_Ace derived data from stellar spectra (Boeche+, 2016)
J/A+A/590/A9 : RGB stars in Galactic GC stellar parameters (Dias+, 2016)
J/A+A/604/A41 : ESO452-SC11 Stellar parameters and abundances (Koch+, 2017)
J/MNRAS/465/501 : APOGEE N-rich stars in inner Galaxy (Schiavon+, 2017)
J/ApJ/848/68 : Abund & RVs of stable and Blazhko RRc stars (Sneden+, 2017)
J/MNRAS/478/1520 : Milky Way globular clusters data (Baumgardt+, 2018)
J/AJ/155/171 : RR Lyrae stars in and around NGC 6441 (Kunder+, 2018)
J/MNRAS/482/5138 : Galactic GC proper motions & velocities (Baumgardt+, 2019)
J/ApJ/908/20 : On use fieldRR Lyrae galactic probes. II. (Crestani+, 2021)
J/ApJ/920/33 : Fe/H estim of 104 RRLyrae from I-light curve (Dekany+, 2021)
J/ApJ/907/47 : Comp, bright & faint Red Clump Starsin MW bulge (Lim+, 2021)
J/MNRAS/505/5978 : Gaia EDR3 view Galactic globular clusters (Vasiliev+, 2021)
J/A+A/662/A75 : CaII spectroscopy of SMC red giants. V. (Parisi+, 2022)
J/A+A/669/A115 : Galactic Bulge GC stars CaT and RV (Geisler+, 2023)
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 9 F9.5 deg RAdeg [273/274] Right Ascension, decimal degrees (J2000)
11- 19 F9.5 deg DEdeg [-28.7/-28.5] Declination, decimal degrees (J2000)
21- 26 F6.3 mag umag [12.9/24]? DECam u-band magnitude
28- 32 F5.3 mag e_umag [0.001/0.9]? Error in umag
34- 39 F6.3 mag gmag [12/22] DECam g-band magnitude
41- 45 F5.3 mag e_gmag [0.001/2] Error in gmag
47- 52 F6.3 mag rmag [11.7/20.5] DECam r-band magnitude
54- 58 F5.3 mag e_rmag [0.001/0.8] Error in rmag
60- 65 F6.3 mag imag [10.8/20]? DECam i-band magnitude
67- 71 F5.3 mag e_imag [0.001/0.9]? Error in imag
73- 78 F6.3 mag zmag [11/20.1]? DECam z-band magnitude
80- 84 F5.3 mag e_zmag [0.001/0.8]? Error in zmag
86- 91 F6.3 mag ymag [9.75/20.31]? DECam y-band magnitude
93- 97 F5.3 mag e_ymag [0.001/2]? Error in ymag
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 19 A19 --- Gaia Gaia DR3 identifier [source_id]
21- 22 A2 --- OFlag Object Flag (1)
25- 34 F10.6 deg RAdeg [273/274] Right Ascension (ICRS at Epoch=2016)
36- 45 F10.6 deg DEdeg [-29/-28] Declination (ICRS at Epoch=2016)
47- 51 F5.3 mas.yr-1 pmRA [2.81/3.99] Proper motion in RA, Gaia DR3
53- 57 F5.3 mas.yr-1 e_pmRA [0.02/0.2] Uncertainty in pmRA
59- 64 F6.3 mas.yr-1 pmDE [-3.99/-3.28] Proper motion in DE, Gaia DR3
66- 70 F5.3 mas.yr-1 e_pmDE [0.02/0.2] Uncertainty in pmDE
72- 76 F5.1 km.s-1 RVel [-74.3/-39.8] Heliocentric Radial Velocity,
Gaia DR3
78- 81 F4.1 km.s-1 e_RVel [1.1/12.4] Uncertainty in RVel
83- 87 F5.2 [-] [Fe/H] [-1.37/-0.69]? Metallicity
89- 91 F3.1 [-] e_[Fe/H] [0.2]? Uncertainty in [Fe/H]
93- 96 F4.2 arcmin Sep [0.36/4.22] Separation from BH 261
--------------------------------------------------------------------------------
Note (1): Object type as follows:
HB = Horizontal Branch Star;
RR = RR Lyrae Star.
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 1 I1 --- Subset [1/2] Subset (1)
3- 21 A19 --- Gaia Gaia DR3 identifier
23- 31 F9.5 deg RAdeg [272/275] Right Ascension (ICRS at Epoch=2016)
33- 41 F9.5 deg DEdeg [-30/-27] Declination (ICRS at Epoch=2016)
43- 47 F5.3 mas.yr-1 pmRA [2.41/4.13] Proper motion in RA, Gaia DR3
49- 53 F5.3 mas.yr-1 e_pmRA [0.02/0.1] Uncertainty in pmRA
55- 60 F6.3 mas.yr-1 pmDE [-5.05/-2.22] Proper motion in DE, Gaia DR3
62- 66 F5.3 mas.yr-1 e_pmDE [0.02/0.07] Uncertainty in pmDE
68- 72 F5.1 km.s-1 RVel [-77.0/-36.2] Heliocentric Radial Velocity,
Gaia DR3
74- 76 F3.1 km.s-1 e_RVel [1.4/4.6] Uncertainty in RVel
78- 82 F5.2 [-] [Fe/H] [-1.51/-0.44]? Metallicity
84- 89 F6.3 arcmin Sep [11.731/60.216] Separation from BH 261
--------------------------------------------------------------------------------
Note (1): Subsets as follows:
1 = Red clump stars;
2 = Giant stars.
--------------------------------------------------------------------------------
History:
From electronic version of the journal
(End) Prepared by [AAS], Coralie Fix [CDS], 19-Apr-2024