J/A+A/556/A98 Star-forming rings in NGC5248 (Van der Laan+, 2013)
Explaining two circumnuclear star forming rings in NGC5248.
van der Laan T.P.R., Schinnerer E., Emsellem E., Meidt S., Dumas G.,
Boeker T., Hunt L., Haan S., Mundell C., Wozniak H.
<Astron. Astrophys. 556, A98 (2013)>
=2013A&A...556A..98V 2013A&A...556A..98V
ADC_Keywords: Galaxies, nearby ; Associations, stellar
Keywords: galaxies: individual: NGC5248 - galaxies: ISM -
galaxies: stellar content
Abstract:
The distribution of gas in the central kiloparsec of a galaxy has a
dynamically rapid evolution. Nonaxisymmetries in the gravitational
potential of the galactic disk, such as a large scale stellar bar or
spiral, can lead to significant radial motion of gaseous material from
larger radii to the central region. The large influx of gas and the
subsequent star formation keep the central region constantly changing.
However, the ability of gas to reach the nucleus proper to fuel an AGN
phase is not guaranteed. Gas inflow can be halted at a circumnuclear
star forming ring several hundred parsec away. The nearby galaxy
NGC5248 is especially interesting in this sense since it is said to
host 2 circumnuclear star forming rings at 100pc and 370pc from its
quiescent nucleus. Here we present new subarcsecond PdBI+30m CO(2-1)
emission line observations of the central region. For the first time
the molecular gas distribution at the smallest stellar ring is
resolved into a gas ring, consistent with the presence of a quiescent
nucleus. However, the molecular gas shows no ring structure at the
larger ring. We combine analyses of the gaseous and stellar content in
the central kiloparsec of this galaxy to understand the gas
distribution and dynamics of this star forming central region. We
discuss the probability of two scenarios leading to the current
observations, given our full understanding of this system, and discuss
whether there are really two circumnuclear star forming rings in this
galaxy.
Description:
IRAM PdBI observations in ABCD configuration were carried out between
January 2009 and December 2010 using the full 6-antenna array. The
correlator was centered at 229.6547GHz, corresponding to a
heliocentric velocity of 1153km/s, to observe the redshifted
12CO(2-1) emission line.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table3.dat 22 308 Star cluster ages, extinctions, and masses in
the circumnuclear star forming rings of NGC5248
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See also:
J/AJ/121/3048 : Multicolor photometry in NGC 1512 and NGC 5248 (Maoz+, 2001)
Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- Star [1/461] Star cluster ID, following Maoz et al.
(2001, Cat. J/AJ/121/3048);
<[MBH2001] NGC 5248 CS NNN> in Simbad
5- 7 I3 Myr Age Cluster age
9- 12 F4.2 mag E(B-V) Extinction
14- 16 F3.1 [Msun] log(M) Cluster mass
18- 22 F5.2 --- chi2/dof Reduced χ2 value
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Acknowledgements:
Tessel van der Laan, vanderlaan(at)iram.fr
(End) T.P.R. van der Laan [IRAM], Patricia Vannier [CDS] 27-Jun-2013