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J/A+A/614/A48   Continuous rise of bulges out of galactic disks   (Breda+, 2018)

The continuous rise of bulges out of galactic disks. Breda I., Papaderos P. <Astron. Astrophys. 614, A48 (2018)> =2018A&A...614A..48B (SIMBAD/NED BibCode)
ADC_Keywords: Galaxy catalogs Keywords: galaxies: spiral - galaxies: bulges - galaxies: evolution Abstract: A key subject in extragalactic astronomy concerns the chronology and driving mechanisms of bulge formation in late-type galaxies (LTGs). The standard scenario distinguishes between classical bulges and pseudo-bulges (CBs and PBs, respectively), the first thought to form monolithically prior to disks and the second gradually out of disks. These two bulge formation routes obviously yield antipodal predictions on the bulge age and bulge-to-disk age contrast, both expected to be high (low) in CBs (PBs). Our main goal is to explore whether bulges in present-day LTGs segregate into two evolutionary distinct classes, as expected from the standard scenario. Other questions motivating this study center on evolutionary relations between LTG bulges and their hosting disks, and the occurrence of accretion-powered nuclear activity as a function of bulge stellar mass M* and stellar surface density Σ*. In this study we have combined three techniques - surface photometry, spectral modeling of integral field spectroscopy data and suppression of stellar populations younger than an adjustable age cutoff with the code REMOVE YOUNG (RY) - toward a systematic analysis of the physical and evolutionary properties (e.g., M* , Σ* and mass-weighted stellar age <t*>M and metallicity <Z*>M, respectively) of a representative sample of 135 nearby (≤130Mpc) LTGs from the CALIFA survey that cover a range between 108.9M and 1011.5M in total stellar mass M*,T. In particular, the analysis here revolves around <δµ9G>, a new distance- and formally extinction-independent measure of the contribution by stellar populations of age ≥9Gyr to the mean r-band surface brightness of the bulge. We argue that <δµ9Gx > offers a handy semi-empirical tracer of the physical and evolutionary properties of LTG bulges and a promising means for their characterization. Description: Photometric, evolutionary and physical quantities for the sample of late-type galaxies from the CALIFA survey, analyzed in the paper. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file ltgs.dat 135 135 Photometric, evolutionary and physical quantities for the galaxy sample under study (table C1)
See also: J/A+A/576/A135 : CALIFA DR2 (Garcia-Benito+, 2015) Byte-by-byte Description of file: ltgs.dat
Bytes Format Units Label Explanations
1- 12 A12 --- Name Galaxy name (name) 14- 18 F5.1 Mpc Dist Assumed distance (distance) 20- 27 F8.6 kpc RB Isophotal radius of the bulge (BrRiso) 29- 36 F8.5 [Msun] logM*T logarithm of the total stellar mass (T_logMnow) (1) 38- 45 F8.5 [Msun] logM*B logarithm of the present-day stellar mass within RB (B_logMnow) (1) 47- 54 F8.5 Gyr <t*B>M Mass-weighted stellar age of the bulge (B_tMass) (1) 56- 63 F8.6 Gyr s_<t*B>M Dispersion of <t*B>M (BtMassE) (1) 65- 72 F8.5 Gyr <t*D>M Mass-weighted stellar age of the disk (D_tMass) (1) 74- 81 F8.6 Gyr s_<t*D>M Dispersion of <t*D>M (DtMassE) (1) 83- 90 F8.6 Sun <Z*B>M Mass-weighted stellar metallicity of the bulge (B_Zmass) (1) 92- 99 F8.6 Sun s_<Z*B>M Dispersion of <Z*B>M (BZmassE) (1) 101-108 F8.6 Sun <Z*D>M Mass-weighted stellar metallicity of the disk (D_Zmass) (1) 110-117 F8.6 Sun s_<Z*D>M Dispersion of <Z*D>M (DZmassE) (1) 119-125 F7.5 [Msun/kpc2] logS*B logarithm of the mean stellar mass surface density in the bulge (B_logSSDensity) (1) 127-135 F9.6 mag <md9G> Mean <δµ9G> (rmag) within RB (DeltaMu_Rb)
Note (1): Quantities were obtained from spectral modeling with STARLIGHT of CALIFA V500 data with the Z4 SSP library and refer to the present-day M* (cf. Sect. 2.2.2).
Acknowledgements: Iris Breda, Iris.Breda(at)
(End) Patricia Vannier [CDS] 28-Dec-2017
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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