J/AJ/146/104 Dwarf galaxies surface brightness profiles. I. (Herrmann+, 2013)
Surface brightness profiles of dwarf galaxies. I. Profiles and statistics.
Herrmann K.A., Hunter D.A., Elmegreen B.G.
<Astron. J., 146, 104 (2013)>
=2013AJ....146..104H 2013AJ....146..104H
ADC_Keywords: Galaxies, photometry ; Morphology
Keywords: galaxies: dwarf - galaxies: fundamental parameters -
galaxies: irregular - galaxies: statistics - galaxies: structure
Abstract:
Radial surface brightness profiles of spiral galaxies are classified
into three types: (I) single exponential, or the light falls off with
one exponential to a break before falling off (II) more steeply, or
(III) less steeply. Profile breaks are also found in dwarf disks, but
some dwarf Type IIs are flat or increasing out to a break before
falling off. Here we re-examine the stellar disk profiles of 141
dwarfs: 96 dwarf irregulars (dIms), 26 Blue Compact Dwarfs (BCDs), and
19 Magellanic-type spirals (Sms). We fit single, double, or even
triple exponential profiles in up to 11 passbands: GALEX FUV and NUV,
ground-based UBVJHK and Hα, and Spitzer 3.6 and 4.5µm. We
find that more luminous galaxies have brighter centers, larger inner
and outer scale lengths, and breaks at larger radii; dwarf trends with
MBextend to spirals. However, the V-band break surface brightness is
independent of break type, MB, and Hubble type. Dwarf Type II and
III profiles fall off similarly beyond the breaks but have different
interiors and IIs break ∼twice as far as IIIs. Outer Type II and III
scale lengths may have weak trends with wavelength, but pure Type II
inner scale lengths clearly decrease from the FUV to visible bands
whereas Type III inner scale lengths increase with redder bands. This
suggests the influence of different star formation histories on
profile type, but nonetheless the break location is approximately the
same in all passbands. Dwarfs continue trends between profile and
Hubble types such that later-type galaxies have more Type II but fewer
Type I and III profiles than early-type spirals. BCDs and Sms are
over-represented as Types III and II, respectively, compared to dIms.
Description:
Our galaxy sample (see Table 1) is from the survey of Hunter &
Elmegreen (2004, Cat. J/AJ/128/2170), which includes 94 dwarf
Irregulars (dIms), 26 Blue Compact Dwarfs (BCDs), and 20
Magellanic-type spirals (Sms).4 (The Sm F567-2 is missing from this
study and two dIms, F473-V1 and F620-V3, have been added.)
UBV images from 27 observing runs are given by Hunter & Elmegreen
(2006, Cat. J/ApJS/162/49) for 136 dwarfs and images from at least one
band of JHK are presented for 41 (26 dIm, 12 BCD, and 3 Sm) from an
additional 9 observing runs. The remaining 5 out of 141 galaxies (DDO
125, Mrk 67, NGC 1705, NGC 2101, and NGC 3109) were observed earlier
with a different detector and so were not included in Hunter &
Elmegreen (2006). Most of the UBV and JHK images were obtained with
the Lowell Observatory 1.1m or 1.8m telescopes.
Satellite UV images were also obtained with the Galaxy Evolution
Explorer (GALEX). GALEX produced images in two passbands: FUV, with a
bandpass of 1350-1750Å, an effective wavelength of 1516Å, and a
resolution of 4" and NUV with a bandpass of 1750-2800Å, an
effective wavelength of 2267Å, and a resolution of 5.6". The FUV
and NUV data are on the AB magnitude system whereas the data in all
other broad bands are on the Johnson/Cousin system. Hunter et al.
(2010AJ....139..447H 2010AJ....139..447H) analyzed surface photometry and derived SF rates
from archival GALEX images of 44 galaxies. (Note that NUV data were
available for DDO 88, DDO 165, and DDO 180 but FUV images were not.)
Hunter et al. (2011AJ....142..121H 2011AJ....142..121H) obtained deep GALEX UV images of
an additional four galaxies and a deeper image of DDO 53. The LITTLE
THINGS team obtained data on another 12 galaxies (Zhang et al.,
2012AJ....143...47Z 2012AJ....143...47Z).
We obtained mid-infrared (3.6 and 4.5{micro}m) images with the
Infrared Array Camera (IRAC) from the Spitzer archives. Hunter et al.
(2006, Cat. J/ApJS/162/49) analyzed data on 21 galaxies in our sample.
Other data were taken by several Spitzer Legacy projects: The Local
Volume Legacy and the Spitzer Infrared Nearby Galaxy Survey.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 155 141 Galaxy sample
table4.dat 114 816 Fit parameters
refs.dat 444 26 References
--------------------------------------------------------------------------------
See also:
J/AJ/144/134 : LITTLE THINGS survey of nearby dwarf galaxies (Hunter+, 2012)
J/AJ/136/2563 : HI Nearby Galaxy Survey, THINGS (Walter+, 2008)
J/ApJS/162/49 : UBV imaging of irregular galaxies (Hunter+, 2006)
J/ApJ/647/1056 : ARAUCARIA project : NGC 6822 Cepheid variables (Gieren+, 2006)
J/AJ/128/2170 : Hα imaging of irregular galaxies (Hunter+, 2004)
J/AJ/127/2031 : Catalog of neighboring galaxies (Karachentsev+, 2004)
J/A+A/398/479 : Local galaxy flows within 5 Mpc (Karachentsev+, 2003)
J/AJ/125/1261 : VI photometry of Sextans A Cepheids (Dolphin+, 2003)
J/AJ/123/3154 : RV light curves of variable stars in Leo A (Dolphin+, 2002)
J/A+AS/128/459 : BV photometry of irregular galaxies (Makarova+ 1998)
J/AJ/116/146 : UGC 6456 HST photometry (Lynds+ 1998)
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 12 A12 --- Name Galaxy name
14-106 A93 --- OName Other names obtained from NED
108-110 A3 --- MT Morphological Hubble type (BCD, Im, Sm) (2)
112-116 F5.1 Mpc Dist Distance
118-122 A5 --- r_Dist Reference for Dist (in refs.dat file) (3)
124-127 F4.2 mag E(B-V) Burstein & Heiles (1984ApJS...54...33B 1984ApJS...54...33B)
foreground reddening
129-134 F6.2 mag BMag ? Absolute B band magnitude (4)
136-147 A12 --- Type Final profile type (G1)
149-155 A7 --- n_Name Additional notes (1)
--------------------------------------------------------------------------------
Note (2): We have used types given by NED:
BCD = Blue Compact Dwarf;
Im = dwarf Irregular;
Sm = Magellanic-type spiral.
Note (3): If no reference is given, the distance was determined from VGSR
given by Vaucouleurs et al. (1991; RC3, Cat. VII/155) and a Hubble
constant of 65km/s/Mpc, as in Hunter & Elmegreen (2006, J/ApJS/162/49).
Note that surface photometry is independent of distance.
Note (4): Calculated from Hunter & Elmegreen (2006, J/ApJS/162/49).
Galaxies without B band data are left blank.
Note (1): Notes as follows:
B = Barred;
PM = Peculiar morphology;
LT = LITTLE THINGS (Hunter et al., 2012, J/AJ/144/134) member;
T = THINGS (Walter et al., 2008, J/AJ/136/2563) member;
VO = V-band only.
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table4.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 12 A12 --- Name Galaxy name
14- 18 A5 --- Band Observational passband (2)
20- 22 A3 --- Type Final profile type (FI, I, II, III) (G1)
24- 31 F8.2 kpc hi ? Inner scale length (3)
33- 40 F8.2 kpc e_hi ? Uncertainty in hRi
42- 46 F5.2 mag/arcsec2 mu0i ? Central surface brightness (4)
48- 51 F4.2 mag/arcsec2 e_mu0i ? Uncertainty in mu0i
53- 57 F5.2 kpc RBr ? Break location
59- 63 F5.2 kpc e_RBr ? Uncertainty in RBr
65- 69 F5.2 mag/arcsec2 mubr ? Surface brightness at RBr (4)
71- 75 F5.2 mag/arcsec2 e_mubr ? Uncertainty in mubr
77- 82 F6.2 kpc ho ? Outer scale length
84- 89 F6.2 kpc e_ho ? Uncertainty in ho
91- 95 F5.2 mag/arcsec2 mu0o ? Outer surface brightness projected
back to the center (4)
97-101 F5.2 mag/arcsec2 e_mu0o ? Uncertainty in mu0o
103-104 I2 --- Ne [1/12]? Number of eliminated points
in that band's profile
106-114 A9 --- n_Ne A series of letters possibly preceded by
an * explain the eliminated data (5)
--------------------------------------------------------------------------------
Note (2): 3.6um, 4.5um, B, FUV, H, Ha, J, K, NUV, U, V.
Note (3): A negative scale length in any broadband filter indicates a scale
length such that the light is brightening; these are only found in the
inner scale lengths. Alternately, a negative/positive scale length in Ha
indicates a scale length such that the light is dimming/brightening; either
can be found in the inner or outer scale lengths.
Note (4): Except for Ha data which are logΣHα in erg/s/pc2.
Note (5): symbols used:
i/m/o = Eliminated data points in the inner/middle/outer third of the profile.
e/d = Eliminated data points are an e=excess (brighter than the fit) or
d=decrement (fainter than the fit),
* = A significant discrepancy from the fit;
B = Profile forced to be broken;
S = Profile forced to single.
An i, m, or o (or a combination thereof) preceded by a 2 indicates the inner,
middle, or outer segment (or a combination) were fit by only two data points.
--------------------------------------------------------------------------------
Byte-by-byte Description of file: refs.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 2 A2 --- Ref Reference number
4- 22 A19 --- BibCode Bibliographic code
24- 45 A22 --- Aut Author's name
47-444 A398 --- Com Comments
--------------------------------------------------------------------------------
Global Notes:
Note (G1): The profile types are
I = single exponential. A profile of Type I has no break location
nor outer fit, so columns 8-15 contain no data.
II = truncated profile (falls off more steeply beyond the break)
FI = flat profile, falls off beyond the break.
III = "anti-truncated" profile (falls off is shallower beyond the break).
Galaxies with two breaks are listed as "inner type + outer type" in
table1, and ones with different types depending on wavelength are
generally listed blue to red.
In table4, a profile that is fit with two breaks is listed on two
lines such that the first line contains the inner fit parameters, the
information for the first break, and the middle fit parameters while
the second line contains only the information about the second break
and the outermost fit parameters. Because the middle fit parameters do
not need to be given twice, columns 4-7 contain no data in the second
line for profiles with two breaks.
History:
From electronic version of the journal
References:
Herrmann et al., Paper II 2016AJ....151..145H 2016AJ....151..145H, Cat. J/AJ/151/145
(End) Greg Schwarz [AAS], Sylvain Guehenneux [CDS] 18-Jul-2014