J/MNRAS/451/3173 Circumnuclear star-forming regions (Alvarez-Alvarez+, 2015)
A comprehensive photometric study of circumnuclear star-forming rings.
I. The sample.
Alvarez-Alvarez M., Diaz A.I., Terlevich E., Terlevich R.
<Mon. Not. R. Astron. Soc., 451, 3173-3191 (2015)>
=2015MNRAS.451.3173A 2015MNRAS.451.3173A (SIMBAD/NED BibCode)
ADC_Keywords: Galaxies, nearby ; Associations, stellar ; Photometry, UBVRI ;
Equivalent widths
Keywords: galaxies: star formation - galaxies: stellar content
Abstract:
We present photometry in U, B, V, R and I continuum bands and in
Hα and Hβ emission lines for a sample of 336 circumnuclear
star-forming regions located in early-type spiral galaxies with
different levels of activity in their nuclei. They are nearby
galaxies, with distances less than 100Mpc, 60 per cent of which are
considered as interacting objects. This survey of 20 nuclear rings
aims to provide insight into their star formation properties as age,
stellar population and star formation rate. Extinction-corrected
Hα luminosities range from 1.3x1038 to 4x1041erg/s, with
most of the regions showing values between 39.5≤logLHα≤40,
which implies masses for the ionizing clusters higher than
2x105M☉. Hα and Hβ images have allowed us to obtain
an accurate measure of extinction. We have found an average value of
AV=1.85 mag. (U-B) colour follows a two maximum distribution around
(U-B)≃-0.7, and -0.3; (R-I) also presents a bimodal behaviour, with
maximum values of 0.6 and 0.9. Reddest (U-B) and (R-I) regions appear
in non-interacting galaxies. Reddest (R-I) regions lie in strongly
barred galaxies. For a significant number of HII regions, the observed
colours and equivalent widths are not well reproduced by single burst
evolutionary theoretical models.
Description:
In order to achieve our scientific goals, we have studied a diverse
population of galaxies with reported circumnuclear rings of SFRs in
the bibliography.
The data were acquired during five observing runs. For the first two
runs (from 1988 to 1990), we used a blue sensitive GEC CCD at the f/15
Cassegrain focus of the 1.0m. Jacobus Kaptein Telescope of the Isaac
Newton Group at the Observatorio del Roque de los Muchachos, La Palma,
Spain. The CCD had 578x385 pixels 22um wide.
The last three observing runs were carried on from 1999 to 2000 at the
Centro Astronomico Hispano Aleman de Calar Alto, Almeria, Spain.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 43 20 Characteristics of the galaxy sample
table5.dat 65 335 *Narrow band results
table6.dat 79 335 Broad-band results
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Note on table5.dat: No correction has been made for the inclination of the
galaxy as explained in the text. Average seeing values were
2 [arcsec full width at half-maximum (FWHM)].
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See also:
J/A+A/556/A98 : Star-forming rings in NGC5248 (Van der Laan+, 2013)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 10 A10 --- Galaxy Galaxy name
11- 23 A13 --- MType Morphological type from RC3 (de Vaucouleurs
et al., 1991, Cat. VII/155)
25- 27 I3 pc/arcsec Scale Angulare scale
29- 37 A9 --- NType Nuclear type (1)
39- 42 F4.1 Mpc Dist Distance
43 A1 --- r_Dist Reference for Distance (2)
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Note (1): Nuclear type is from Veron-Cetty & Veron (2006A&A...455..773V 2006A&A...455..773V,
Cat. VII/248), if the galaxy is present in the catalogue. Otherwise nuclear
type is from the NED. The National Extragalactic Database (NED), is operated
by the Jet Propulsion Laboratory, California Institute of Technology, under
contract with the National Aeronautics and Space Administration.
Note (2): References as follows:
b = Telesco & Harper, 1980ApJ...235..392T 1980ApJ...235..392T
c = Bottinelli et al. (1984).
d = Garcia Barreto, 1991A&A...244..272G 1991A&A...244..272G
e = Freedman et al., 1994ApJ...435L..31F 1994ApJ...435L..31F
f = Tully, 1988, Nearby Galaxies Catalog (Cambridge Univ. Press:
Cambridge, Cat. VII/145).
g = Feldmeier, Ciardullo & Jacoby, 1997, Cat. J/ApJ/479/231
h = Gonzalez-Delgado & Perez, 1996MNRAS.281..781G 1996MNRAS.281..781G
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Byte-by-byte Description of file: table5.dat
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Bytes Format Units Label Explanations
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1- 10 A10 --- Galaxy Galaxy name
11- 12 I2 --- Reg ? Region number
13- 19 A7 --- m_Reg Multiplicity index (ab) or Nucleus
21- 23 F3.1 arcsec Dist ?=- Distance for the galaxy nucleus
26- 30 F5.1 arcsec Px ?=- Position from the galaxy nucleus (1)
32- 36 F5.1 arcsec Py ?=- Position from the galaxy nucleus (1)
39- 42 F4.1 [10-7W] logL(Ha) ?=- Hα luminosity
44- 47 F4.2 --- DFlux/Flux ?=- Error in the flux calculation,
δFlux/Flux (2)
50- 54 F5.1 0.1nm EWHa ?=- Hα equivalent width
56- 60 F5.1 0.1nm EWHb ?=- Hβ equivalent width
62- 65 F4.2 mag AV ?=- Visual extinction
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Note (1): Px is the position along O-E axis (East left)
Py is the position along S-N axis (North up)
Note (2): Measure of error in the flux calculation as explained in the text.
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Byte-by-byte Description of file: table6.dat
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Bytes Format Units Label Explanations
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1- 10 A10 --- Galaxy Galaxy name
11- 12 I2 --- Reg ? Region number
13- 19 A7 --- m_Reg Multiplicity index (ab) or Nucleus
22- 26 F5.1 pc Rad ? Radius of the region (1)
28- 32 F5.3 kpc Dist ? Distance for the galaxy nucleus
34- 38 F5.1 mag RMAG ? Absolute R magnitude
40- 42 F3.1 mag e_RMAG ? rms uncertainty on RMAG (2)
44- 48 F5.2 mag U-B ? U-B colour index
50- 51 A2 --- leU-B [≤ ] Limit flag on e_U-B
52- 55 F4.2 mag e_U-B ? rms uncertainty on U-B
57- 61 F5.2 mag B-R ? B-R colour index
63- 66 F4.2 mag e_B-R ? rms uncertainty on B-R
68- 72 F5.2 mag R-I ? R-I colour index
74- 75 A2 --- leR-I [≤ ] Limit flag on e_R-I
76- 79 F4.2 mag e_R-I ? rms uncertainty on R-I
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Note (1): Linear radius of each region is affected by a mean error due to:
seeing conditions, size estimation, etc. of about 20 per cent on average.
Note (2): Error in RMAG and colours have been computed using radius of +1
and -1 pixels as explained in the text.
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Acknowledgements:
Mar Alvarez-Alvarez, malvar1(at)ing.uc3m.es
(End) Patricia Vannier [CDS] 21-Jan-2016