J/A+A/551/A81 NGC 6951 intensity and velocity maps (van der Laan+, 2013)
How does star formation proceed in the circumnuclear starburst ring of NGC 6951?
van der Laan T.P.R., Schinnerer E., Emsellem E., Hunt L.K., McDermid R.M.,
Liu G.
<Astron. Astrophys. 551, A81 (2013)>
=2013A&A...551A..81V 2013A&A...551A..81V
ADC_Keywords: Galaxies, Seyfert ; Spectroscopy ; Radial velocities
Keywords: galaxies: individual: NGC 6951 - galaxies: ISM -
galaxies: stellar content
Abstract:
Gas inflowing along stellar bars is often stalled at the location of
circumnuclear rings, which form an effective reservoir for massive
star formation and thus shape the central regions of galaxies.
However, how exactly star formation proceeds within these
circumnuclear starburst rings is the subject of debate. Two main
scenarios for this process have been put forward. In the first, the
onset of star formation is regulated by the total amount of gas
present in the ring with star forming starting, once a mass threshold
has been reached, in "random" positions within the ring like
"popcorn". In the second, star formation primarily takes place
near the locations where the gas enters the ring. This scenario has
been dubbed "pearls-on-a-string". Here we combine new optical IFU
data covering the full stellar bar with existing multiwavelength data
to study the 580pc radius circumnuclear starburst ring in detail in
the nearby spiral galaxy NGC 6951. Using Hubble Space Telescope
(HST) archival data together with SAURON and OASIS IFU data, we
derive the ages and stellar masses of star clusters, as well as the
total stellar content of the central region.
Description:
Investigators using these data are requested to reference the above
paper in any publication.
Objects:
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RA (2000) DE Designation(s)
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20 37 14.08 +66 06 20.3 NGC 6951 = UGC 11604
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
list.dat 93 9 List of maps
maps/* . 9 Individual FITS files
table4.dat 91 83 Candidate star clusters detected with
IRAF/DAOPHOT and SExtractor
table5.dat 22 48 Star cluster ages, extinctions, and masses
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Byte-by-byte Description of file: list.dat
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Bytes Format Units Label Explanations
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1- 2 I2 h RAh ? Right Ascension of center (J2000)
4- 5 I2 min RAm ? Right Ascension of center (J2000)
7- 12 F6.3 s RAs ? Right Ascension of center (J2000)
14 A1 --- DE- Declination sign of center (J2000)
15- 16 I2 deg DEd ? Declination of center (J2000)
18- 19 I2 arcmin DEm ? Declination of center (J2000)
21- 25 F5.2 arcsec DEs ? Declination of center (J2000)
28- 31 I4 pix Nx Number of pixels along X-axis
32 A1 --- --- [x]
33- 36 I4 pix Ny Number of pixels along Y-axis
37 A1 --- --- [x]
38 I1 --- Nz ? Number of slices
40- 51 A12 --- FileName Name of FITS file in subdirectory maps
53- 93 A41 --- Title Title of the file (1)
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Note (1): For OASIS maps, orientation: long edge rotated by 48deg wrt NE.
For SAURON datacube, data cube with 3 extensions, orientation: along
large scale stellar bar.
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Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
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1- 2 I2 --- ID Star cluster candidate sequential number (1)
3 A1 --- n_ID [*] Note on ID (2)
5- 8 F4.1 arcsec oRA Offset in right ascension (3)
10- 13 F4.1 arcsec oDE Offset in declination (3)
15- 19 F5.1 mag M330 ?=- Absolute magnitude in F330W band HST image (4)
21- 25 F5.2 mag e_M330 ?=- rms uncertainty on M330
27- 31 F5.1 mag M547 ?=- Absolute magnitude in F547W band HST image (4)
33- 36 F4.2 mag e_M547 ?=- rms uncertainty on M547
38- 42 F5.1 mag M606 ?=- Absolute magnitude in F606W band HST image (4)
44- 47 F4.2 mag e_M606 ?=- rms uncertainty on M606
49- 53 F5.1 mag M658 ?=- Absolute magnitude in F658W band HST image (4)
55- 58 F4.2 mag e_M658 ?=- rms uncertainty on M658
60- 64 F5.1 mag M814 ?=- Absolute magnitude in F814W band HST image (4)
66- 69 F4.2 mag e_M814 ?=- rms uncertainty on M814
71- 75 F5.1 mag M110 ?=- Absolute magnitude in F110W band HST image (4)
77- 80 F4.2 mag e_M110 ?=- rms uncertainty on M110
82- 86 F5.1 mag M160 ?=- Absolute magnitude in F160W band HST image (4)
88- 91 F4.2 mag e_M160 ?=- rms uncertainty on M547
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Note (1): Some candidates could have 2 entries.
Note (2): * indicates candidates that could not be fitted with an acceptable
star cluster model in (see Sect. 6).
Note (3): Projected offset in arcseconds from the photometric nucleus
at position 20:37:14.123+66:06:20.09 (J2000)
Note (4): Absolute magnitudes as m-M=31.9.
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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- 2 I2 --- Seq Star cluster candidate sequential number
4- 6 I3 Myr Age Age from χ2 fitting
8- 11 F4.2 mag E(B-V) Colour excess from χ2 fitting
13- 15 F3.1 [Msun] logMass Mass from χ2 fitting
17- 22 F6.2 --- chi2/df χ2/dof value
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Acknowledgements:
Tessel van der Laan, vdlaan(at)mpia.de
History:
* 26-Feb-2013: On-line version with FITS maps
* 16-Oct-2013: tables 4 and 5 added (from elctronic version)
(End) Tessel van der Laan [Grenoble, France], Patricia Vannier [CDS] 21-Jan-2013