J/ApJ/710/1664 BV photometry in Leo IV and Leo V dSphs (de Jong+, 2010)
The enigmatic pair of dwarf galaxies Leo IV and Leo V: coincidence or common
origin?
de Jong J.T.A., Martin N.F., Rix H.-W., Smith K.W., Jin S., Maccio A.V.
<Astrophys. J., 710, 1664-1671 (2010)>
=2010ApJ...710.1664D 2010ApJ...710.1664D
ADC_Keywords: Galaxies, photometry ; Photometry, UBV ; Galaxies, nearby
Keywords: galaxies: individual (Leo IV dSph, Leo V dSph) - Local Group
Abstract:
We have obtained deep photometry in two 1°x1° fields covering
the close pair of dwarf spheroidal galaxies Leo IV and Leo V and part
of the area in between. From the distribution of likely red giant
branch (RGB) and horizontal-branch (HB) stars in the data set, we find
that both Leo IV and Leo V are significantly larger than indicated by
previous measurements based on shallower data. With a half-light
radius of rh=4.6'±0.8' (206±36pc) and rh=2.6'±0.6'
(133±31pc), respectively, both systems are now well within the
physical size bracket of typical dwarf spheroidal Milky Way
satellites. Both are also found to be significantly elongated with an
ellipticity of ε∼0.5, a characteristic shared by many of the
fainter (MV>-8) Milky Way dwarf spheroidals. The large spatial
extent of our survey allows us to search for extra-tidal features in
the area between the two dwarf galaxies with unprecedented
sensitivity. The spatial distribution of candidate RGB and HB stars in
this region is found to be non-uniform at the ∼3σ level. We
investigate different scenarios to explain the close proximity of Leo
IV and Leo V, and the possible tidal bridge between them.
Description:
Deep, wide-field photometry in the Johnson B and V filters was
obtained for two 1°x1° fields, using the LAICA imager on the
3.5m telescope at the Calar Alto observatory. Observations were
carried out during the nights of 2009 February 24 and 25.
Objects:
----------------------------------------------------------------
RA (2000) DE Designation(s)
----------------------------------------------------------------
11 32 58.6 -00 33 06 NAME LEO IV = NAME LEO IV DWARF GALAXY
11 31 08.4 +02 12 57 NAME LEO V = NAME LEO V
----------------------------------------------------------------
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 55 24738 Photometric data
--------------------------------------------------------------------------------
See also:
J/ApJS/191/352 : Abundances in stars of Milky Way dwarf satellites (Kirby+,
2010)
J/ApJ/694/L144 : Spectroscopic study of Leo V dSph (Walker+, 2009)
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 A4 --- ID Chip identification number (1)
6- 14 F9.5 deg RAdeg Right Ascension in decimal degrees (J2000)
16- 23 F8.5 deg DEdeg Declination in decimal degrees (J2000)
25- 30 F6.3 mag Bmag The Johnson B band magnitude
32- 36 F5.3 mag e_Bmag The 1σ error in Bmag
38- 43 F6.3 mag Vmag The Johnson V band magnitude
45- 49 F5.3 mag e_Vmag The 1σ error in Vmag
51- 55 F5.3 mag E(B-V) The E(B-V) color excess
--------------------------------------------------------------------------------
Note (1): The first digit of the chip ID indicates the field, where a
"0" stands for the Northern field containing Leo V and a
"1" for the Southern field containing Leo IV;
the integers following the underscore signify the exposure and the
chip number, respectively, both running from 1 to 4.
--------------------------------------------------------------------------------
History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 29-Mar-2012