J/ApJ/716/942 Bulges of nearby galaxies with Spitzer (Fisher+, 2010)
Bulges of nearby galaxies with Spitzer: scaling relations in pseudobulges and
classical bulges.
Fisher D.B., Drory N.
<Astrophys. J., 716, 942-969 (2010)>
=2010ApJ...716..942F 2010ApJ...716..942F
ADC_Keywords: Galaxies, nearby ; Photometry, infrared ; Morphology
Keywords: galaxies: bulges - galaxies: evolution - galaxies: formation -
galaxies: fundamental parameters - galaxies: structure
Abstract:
We investigate scaling relations of bulges using bulge-disk
decompositions at 3.6um and present bulge classifications for 173 E-Sd
galaxies within 20Mpc. Pseudobulges and classical bulges are
identified using Sersic index, Hubble Space Telescope morphology, and
star formation activity (traced by 8um emission). In the near-IR
pseudobulges have nb<2 and classical bulges have nb>2, as found in
the optical. Sersic index and morphology are essentially equivalent
properties for bulge classification purposes. We confirm, using a much
more robust sample, that the Sersic index of pseudobulges is
uncorrelated with other bulge structural properties, unlike for
classical bulges and elliptical galaxies. Also, the half-light radius
of pseudobulges is not correlated with any other bulge property. We
also find a new correlation between surface brightness and pseudobulge
luminosity; pseudobulges become more luminous as they become more
dense.
Description:
We use data from Spitzer to perform bulge-disk decompositions at
3.6um, where the data are less affected by gradients in dust and
stellar populations than in the optical bands. Also, we use 8um mid-IR
data to estimate star formation rates. We also wish to compare the
location of pseudobulges and classical bulges in parameter space to
that of elliptical galaxies. We therefore include a set of elliptical
galaxies as a control sample from Kormendy et al. (2009, Cat.
J/ApJS/182/216).
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 41 145 Sample galaxy properties
table2.dat 92 145 Derived parameters
--------------------------------------------------------------------------------
See also:
VII/155 : Third Reference Cat. of Bright Galaxies (RC3) (de Vaucouleurs+ 1991)
VII/145 : Nearby Galaxies Catalogue (NBG) (Tully 1988)
J/ApJS/182/216 : Surface photometry of Virgo ellipticals (Kormendy+, 2009)
J/AJ/136/773 : Structure of classical bulges and pseudobulges (Fisher+, 2008)
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 8 A8 --- Name Galaxy name
10- 16 A7 --- Type Morphological type taken from RC3
18- 22 F5.2 Mpc Dist Distance
24 I1 --- r_Dist Distance reference (1)
26- 31 F6.2 mag BMag Absolute B-band magnitude
33- 36 F4.2 mag B-V ? B-V color index
38- 41 F4.2 [pc] logD25 Isophotal diameter
--------------------------------------------------------------------------------
Note (1): Distance reference as follows:
1 = Tully & Fisher 1988cng..book.....T 1988cng..book.....T (see also VII/145);
2 = Tonry et al. 2001ApJ...546..681T 2001ApJ...546..681T;
3 = de Vaucouleurs et al. 1991, Cat. VII/155 (RC3)
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 8 A8 --- Name Galaxy name
10 A1 --- B [P/C/ ] Bulge morphology: P=pseudobulge,
C=classical bulge
12- 15 F4.2 --- nb The bulge Sersic index
17- 20 F4.2 --- e_nb nb uncertainty
22- 27 F6.2 mag M3.6 3.6um magnitude of the bulge
(M3.6Sersic)
29- 32 F4.2 mag e_M3.6 M3.6 uncertainty
34- 37 F4.2 [pc] log(re) Log of the half-light radius re
39- 42 F4.2 [pc] e_log(re) log(re) uncertainty
44- 48 F5.2 mag/arcsec2 mue The average surface brightness within
the half-light radius (2)
50- 53 F4.2 mag/arcsec2 e_mue mue uncertainty
55- 59 F5.2 mag/arcsec2 mud Surface brightness (µdisk0,3.6)
61- 64 F4.2 mag/arcsec2 e_mud mud uncertainty
66- 69 F4.2 [pc] log(h) Log of the scale length of the outer disk
71- 74 F4.2 [pc] e_log(h) log(h) uncertainty
76- 81 F6.2 mag M8 ? 8um magnitude of the bulge, dominated
by dust emission (M8,dust) (3)
83- 87 F5.2 mag 3.6-8 ? M3.6-M8.0_ mid-IR color index
89- 92 F4.2 mag e_3.6-8 ? 3.6-8 uncertainty
--------------------------------------------------------------------------------
Note (2): The average surface brightness within the half-light radius, <µe>
is given by <µe≥m3.6+2.5log(πre2) where m3.6 is the
magnitude in 3.6um. See section 3.2 for further details.
Note (3): We calculate M8,dust using the relation from Helou et al.
(2004ApJS..154..253H 2004ApJS..154..253H), where M8,dust=-2.5xlog10(L8-0.232xL3.6)
where L3.6 is the bulge luminosity at 3.6um. See section 6.1 for
further details.
--------------------------------------------------------------------------------
History:
From electronic version of the journal
(End) Emmanuelle Perret [CDS] 31-May-2012