J/ApJ/823/157 LOS velocities & [Fe/H] of Pal 5 tidal stream (Ishigaki+, 2016)
Line-of-sight velocity and metallicity measurements of the Palomar 5 tidal
stream.
Ishigaki M.N., Hwang N., Chiba M., Aoki W.
<Astrophys. J., 823, 157 (2016)>
=2016ApJ...823..157I 2016ApJ...823..157I (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, globular ; Abundances, [Fe/H] ; Radial velocities ;
Photometry, SDSS ; Spectra, infrared
Keywords: globular clusters: individual: Palomar 5;
stars: abundances; stars: kinematics and dynamics
Abstract:
We present Subaru/Faint Object Camera and Spectrograph and Keck/Deep
Imaging Multi-Object Spectrometer medium-resolution spectroscopy of a
tidally disrupting Milky Way (MW) globular cluster Palomar 5 (Pal 5)
and its tidal stream. The observed fields are located to cover an
angular extent of ∼17° along the stream, providing an opportunity
to investigate a trend in line-of-sight velocities (Vlos) along the
stream, which is essential to constrain its orbit and underlying
gravitational potential of the MW's dark matter halo. A spectral
fitting technique is applied to the observed spectra to obtain stellar
parameters and metallicities ([Fe/H]) of the target stars. The 19
stars most likely belonging to the central Pal 5 cluster have a mean
Vlos of -58.1±0.7km/s and metallicity [Fe/H]=-1.35±0.06dex, both
of which are in good agreement with those derived in previous
high-resolution spectroscopic studies. Assuming that the stream stars
have the same [Fe/H] as the progenitor cluster, the derived [Fe/H] and
Vlos values are used to estimate the possible Vlos range of the
member stars at each location along the stream. Because of the heavy
contamination of the field MW stars, the estimated Vlos range
depends on prior assumptions about the stream's Vlos, which
highlights the importance of more definitely identifying the member
stars using proper motion and chemical abundances to obtain unbiased
information of Vlos in the outer part of the Pal 5 stream. The
models for the gravitational potential of the MW's dark matter halo
that are compatible with the estimated Vlos range are discussed.
Description:
The observations were carried out using the FOCAS on the Subaru
telescope on 2011 June 29 and 30 (wavelength range of ∼7600-8600Å;
R∼7000) and the Deep Imaging Multi-Object Spectrometer (DEIMOS) on the
Keck II telescope on 2013 May 12 and 13 (wavelength range
∼6500-9000Å with R∼6000).
Objects:
--------------------------------------------------------
RA (ICRS) DE Designation(s)
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15 16 05.30 -00 06 41.0 Pal 5 = NAME Serpens Dwarf
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File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table4.dat 72 19 Identified Pal 5 member stars in the FOCAS fields
table5.dat 53 130 Stars in the DEIMOS fields selected by the CMD,
[Fe/H] and proper motion criteria
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See also:
I/324 : The Initial Gaia Source List (IGSL) (Smart, 2013)
II/294 : The SDSS Photometric Catalog, Release 7 (Adelman-McCarthy+, 2009)
J/ApJ/819/1 : Wide-field photometry of the GC Palomar 5 (Ibata+, 2016)
J/ApJ/783/130 : Parallaxes of high mass star forming regions (Reid+, 2014)
J/ApJ/753/64 : Detailed abundances for 97 metal-poor stars (Ishigaki+, 2012)
J/A+A/525/A90 : Thick disc vertical properties (Katz+, 2011)
J/A+A/512/A54 : Teff and Fbol from Infrared Flux Method (Casagrande+, 2010)
J/ApJ/705/328 : Abundance measurements in Sculptor dSph (Kirby+, 2009)
J/A+A/416/1117 : Abundances in the early Galaxy (Cayrel+, 2004)
http://www.sdss.org/ : SDSS home page
Byte-by-byte Description of file: table4.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 A3 --- Field Subaru/FOCAS field name (CE1 or CE2)
6- 8 A3 --- Name Star name within the field (s1 to s24)
10- 18 F9.5 deg RAdeg Right ascension in decimal degrees (J2000)
20- 27 F8.5 deg DEdeg Declination in decimal degrees (J2000)
29- 33 F5.1 km/s Vlos [-66/-51] Line-of-sight velocity
35- 38 I4 K Teff [4902/5927] Effective temperature
40- 42 F3.1 [cm/s2] logg [1.8/5] Spectroscopic log of surface gravity
44- 48 F5.2 [Sun] [Fe/H] [-1.9/-1] Spectroscopic abundance [Fe/H]
50- 54 F5.2 [Sun] [a/Fe] [-0.3/0.7] Spectroscopic abundance [α/Fe]
56- 58 F3.1 [cm/s2] logg2 [2.5/4] Photometric log of surface gravity
60- 64 F5.2 [Sun] [Fe/H]2 [-1.8/-1] Photometric abundance [Fe/H]
66- 69 F4.2 [Sun] [a/Fe]2 [0.08/1.5] Photometric abundance [α/H]
71- 72 I2 --- S/N [10/41] Signal to noise ratio
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Byte-by-byte Description of file: table5.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 A4 --- Field Keck/DEIMOS field name (FD1 to FD10)
6- 8 I3 --- Name [1/80] Star name within the field
10- 18 F9.5 deg RAdeg Right Ascension in decimal degrees (J2000)
20- 26 F7.4 deg DEdeg Declination in decimal degrees (J2000)
28- 32 F5.2 mag gmag0 [17/20.9] Extinction corrected SDSS g band
magnitude
34- 39 F6.1 km/s HRV [-306/341] Heliocentric line-of-sight velocity
41- 43 F3.1 km/s e_HRV [1/10] Error in HRV
45- 49 F5.2 --- [Fe/H] [-2.1/-0.6] Metallicity
51- 51 A1 --- LOS [ny] Status of line-of-sight velocity
criterion (1)
53 A1 --- f_Name [K] Flag on FD3-008 (2)
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Note (1): "y" for objects with a line-of-sight velocity (Vlos) in a range
-100 <Vlos< -20km/s (minimize contamination from the field MW stars;
see section 4.2), "n" otherwise.
Note (2):
K = observed in common with Kuzma et al. (2015MNRAS.446.3297K 2015MNRAS.446.3297K) (P1238216).
The line-of-sight velocity is in good agreement (-59.8km/s).
Flag added by CDS; see section 2.3.
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 08-Aug-2016