J/ApJ/833/167 PAndAS view of Andromeda satellites. II. (Martin+, 2016)
The PAndAS view of the Andromeda satellite system.
II. Detailed properties of 23 M31 dwarf spheroidal galaxies.
Martin N.F., Ibata R.A., Lewis G.F., McConnachie A., Babul A., Bate N.F.,
Bernard E., Chapman S.C., Collins M.M.L., Conn A.R., Crnojevic D.,
Fardal M.A., Ferguson A.M.N., Irwin M., Mackey A.D., McMonigal B.,
Navarro J.F., Rich R.M.
<Astrophys. J., 833, 167-167 (2016)>
=2016ApJ...833..167M 2016ApJ...833..167M (SIMBAD/NED BibCode)
ADC_Keywords: Galaxies, nearby ; Magnitudes, absolute ; Photometry, surface
Keywords: galaxies: dwarf; Local Group
Abstract:
We present a comprehensive analysis of the structural properties and
luminosities of the 23 dwarf spheroidal galaxies that fall within the
footprint of the Pan-Andromeda Archaeological Survey (PAndAS). These
dwarf galaxies represent the large majority of Andromeda's known
satellite dwarf galaxies and cover a wide range in luminosity
(-11.6≲MV≲-5.8 or 104.2≲L≲106.5L☉) and surface
brightness (25.1≲µ0≲29.3mag/arcsec2). We confirm most
previous measurements, but we find And XIX to be significantly larger
than before (rh=3065-935+1065pc, MV=-10.1-0.4+0.8) and
cannot derive parameters for And XXVII as it is likely not a bound
stellar system. We also significantly revise downward the luminosities
of And XV and And XVI, which are now MV~-7.5 or L∼105L☉.
Finally, we provide the first detailed analysis of Cas II/And XXX, a
fairly faint system (MV=-8.0-0.3+0.4) of typical size
(rh=270±50pc), located in close proximity to the two bright
elliptical dwarf galaxies NGC 147 and NGC 185. Combined with the set
of homogeneous distances published in an earlier contribution, our
analysis dutifully tracks all relevant sources of uncertainty in the
determination of the properties of the dwarf galaxies from the PAndAS
photometric catalog. We further publish the posterior probability
distribution functions of all the parameters we fit for in the form of
MCMC chains available online; these inputs should be used in any
analysis that aims to remain truthful to the data and properly account
for covariance between parameters.
Description:
The specifics of the design, acquisition, reduction, and calibration
of the Pan-Andromeda Archaeological Survey (PAndAS) survey have been
explained in detail in previous contributions from our collaboration
(e.g., Ibata+ 2014ApJ...780..128I 2014ApJ...780..128I).
This Canada-France-Hawaii Telescope (CFHT) Large Program was built on
two previous CFHT surveys led by R. Ibata and A. McConnachie (Ibata+
2007ApJ...671.1591I 2007ApJ...671.1591I; McConnachie+ 2008ApJ...688.1009M 2008ApJ...688.1009M), which were
further complemented by ∼230hr of observation with the same wide-field
imager, MegaCam, in order to cover a contiguous region of ∼390deg2
within ∼150kpc of M31 and ∼50kpc of its companion M33.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 96 23 Derived structural parameters of the dwarf galaxies
table2.dat 70 23 Derived luminosity-related properties of
the dwarf galaxies
table3.dat 109 11500 *Chains generated by the algorithm for the
23 dwarf spheroidal galaxies
--------------------------------------------------------------------------------
Note on table3.dat: Table 3 is a concatenation of the 23 files contained in
apjaa45d0.tar.gz file. Each file contains 500 randomly selected drawings
from each chain for a single galaxy. Each row corresponds to a single drawing.
--------------------------------------------------------------------------------
See also:
J/ApJ/798/77 : Metallicity of RGB stars in 6 M31 dwarf galaxies (Ho+, 2015)
J/ApJ/789/147 : Star formation histories of LG dwarf galaxies (Weisz+, 2014)
J/ApJ/776/80 : PAndAS view of Andromeda satellites. I. (Martin+, 2013)
J/ApJ/768/172 : Kinematic analysis of red giant in M31 dSphs (Collins+, 2013)
J/ApJ/758/11 : Bayesian distances to M31 satellites (Conn+, 2012)
J/AJ/144/4 : Dwarf galaxies in the Local Group (McConnachie+, 2012)
J/MNRAS/380/281 : Faint galactic satellites spectrosc. survey (Martin+, 2007)
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 8 A8 --- Gal Galaxy Name
10- 15 A6 --- Flag Flag(s) on Gal or other name (G1)
17- 18 I2 h RAh Hour of right ascension (J2000)
20- 21 I2 min RAm Minute of right ascension (J2000)
23- 26 F4.1 s RAs Second of right ascension (J2000)
28- 30 F3.1 s e_RAs [0.3/3] RA uncertainty
32 A1 --- DE- Sign of declination (J2000)
33- 34 I2 deg DEd Degree of declination (J2000)
36- 37 I2 arcmin DEm Arcminute of declination (J2000)
39- 40 I2 arcsec DEs Arcsecond of declination (J2000)
42- 43 I2 arcsec e_DEs [4/53] DE uncertainty
45- 48 F4.2 --- ell [0/0.7] Ellipticity ε
50- 53 F4.2 --- e_ell [0/0.5] Negative error on ell
55- 58 F4.2 --- E_ell [0.02/0.5] Positive error on ell
60- 62 I3 deg PA [-20/140] Position angle θ
64- 65 I2 deg e_PA [3/90] Negative error on PA
67- 68 I2 deg E_PA [3/90] Positive error on PA
70- 73 F4.1 arcmin rh [0.4/14.2] Half-light radius in arcminutes
75- 77 F3.1 arcmin e_rh [0.1/2] Negative error on rh
79- 81 F3.1 arcmin E_rh [0.1/3.4] Positive error on rh
83 A1 --- u_rhpc [~] Uncertainty flag on rhpc
84- 87 I4 pc rhpc Half-light radius in parsecs (G2)
89- 92 I4 pc e_rhpc [15/1065]? Negative error on rhpc
94- 96 I3 pc E_rhpc [30/935]? Positive error on rhpc
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 8 A8 --- Gal Galaxy name
10- 15 A6 --- Flag Flag(s) on Gal or other name (G1)
17- 20 F4.1 mag Vmag [12.4/18.5] Apparent magnitude mv,0
22- 24 F3.1 mag e_Vmag [0.2/0.5] Negative uncertainty on Vmag
26- 28 F3.1 mag E_Vmag [0.2/0.7] Positive uncertainty on Vmag
30- 34 F5.1 mag VMag [-11.6/-5.8] Absolute magnitude Mv,0 (G2)
36- 38 F3.1 mag e_VMag [0.2/1] Negative uncertainty on VMag
40- 42 F3.1 mag E_VMag [0.2/0.9] Positive uncertainty on VMag
44- 47 F4.2 [Lsun] logL [4.2/6.6] Log of the luminosity of
the dwarf galaxy (G2)
49- 52 F4.2 [Lsun] e_logL [0.09/0.4] Negative uncertainty on logL
54- 57 F4.2 [Lsun] E_logL [0.09/0.4] Positive uncertainty on logL
59- 62 F4.1 mag/arcsec2 mu0 [25/29.3] Central surface brightness
64- 66 F3.1 mag/arcsec2 e_mu0 [0.2/1] Negative uncertainty on mu0
68- 70 F3.1 mag/arcsec2 E_mu0 [0.2/1] Positive uncertainty on mu0
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 8 A8 --- Gal Galaxy name
10- 19 F10.6 deg RAdeg Right ascension of the centroid (J2000)
21- 30 F10.6 deg DEdeg Declination of the centroid (J2000)
32- 35 F4.2 --- ell Ellipticity ε
37- 43 F7.1 deg PA [-90/230] Position angle θ
45- 49 F5.2 arcmin rh [0.2/29.4] Half-light radius rh
in arcminutes (1)
51- 56 I6 pc rhpc [47/7120] Half-light radius rh
in parsecs (1)
58- 61 F4.1 mag Vmag [11.8/21.4] Apparent magnitude mv,0
63- 67 F5.1 mag VMag [-12.2/-2.6] Absolute magnitude Mv,0 (2)
69- 81 F13.2 [Lsun] logL [2.9/6.8] Log of the luminosity of
the dwarf galaxy (log10(LV/L☉)
83-100 F18.2 mag/arcsec2 mu0 [23.7/31] Central surface brightness
102-109 F8.2 mag DM [22.8/25.8] Distance modulus from
Conn+ (2012, J/ApJ/758/11)
--------------------------------------------------------------------------------
Note (1): The half-light radius as determined using a distance modulus value
randomly drawn from the relevant chain provided by
Conn+ (2012, J/ApJ/758/11).
Note (2): Absolute magnitude MV,0, determined using the same distance modulus
value as explain in Note (1) (Conn+ 2012, J/ApJ/758/11).
--------------------------------------------------------------------------------
Global notes:
Note (G1): Flag as follows:
b = Substructure in the field may impact the structural parameters.
c = Stricter priors were used to ensure convergence.
See the text for more details
Note (G2): Calculated using the posterior heliocentric distance PDFs calculated
by Conn+ (2012, J/ApJ/758/11).
--------------------------------------------------------------------------------
History:
From electronic version of the journal
References:
Martin et al. Paper I. 2013ApJ...776...80M 2013ApJ...776...80M Cat. J/ApJ/776/80
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 24-Apr-2017