J/AJ/117/1708 NGC 1741 HST photometry (Johnson+, 1999)
The very young starburst merger system NGC 1741.
Johnson K.E., Vacca W.D., Leitherer C., Conti P.S., Lipscy S.J.
<Astron. J. 117, 1708 (1999)>
=1999AJ....117.1708J 1999AJ....117.1708J
ADC_Keywords: Associations, stellar ; Photometry, photographic ;
Photometry, ultraviolet
Mission_Name: HST
Keywords: galaxies: individual (NGC 1741) - galaxies: interactions -
galaxies: irregular - galaxies: photometry - galaxies: starburst -
galaxies: star clusters
Abstract:
We use Hubble Space Telescope (HST) Faint Object Camera (FOC)
ultraviolet (UV) and WFPC2 optical images in conjunction with UV
spectroscopic observations taken with the Goddard High Resolution
Spectrograph to examine the star formation history and properties of
the interacting galaxy system NGC 1741 in the Hickson Compact Group
31. The high spatial resolution afforded by HST has allowed us to
identify a large number of starburst knots, or "superstar clusters"
(SSCs), in the starburst regions of this system. Photometry of these
SSCs in the UV and optical bands indicates that most of these objects
have ages of a few Myr, with a few up to ∼100Myr, and masses between
104 and 106M☉. The estimated age is confirmed by a spectral
synthesis analysis of one knot for which we have obtained a UV
spectrum. The V-band luminosity function of the SSCs is well
represented by a power law Φ(L)∼L-α with an index of -1.85,
with no evidence of a turnover brighter than the completeness limit.
These properties are in good agreement with those found for SSCs in
other starburst galaxies. Our results support the suggestion that some
of these SSCs may be extremely young globular clusters formed in a
relatively recent starburst episode that has been triggered by a
merger event.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 96 434 Magnitudes measured for the SSCs in NGC 1741
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- [JVL99] Sequential number
4 A1 --- f_[JVL99] [*] Note on [JVL99] (1)
6 I1 h RAh Right ascension (J2000)
8- 9 I2 min RAm Right ascension (J2000)
11- 15 F5.2 s RAs Right ascension (J2000)
17 A1 --- DE- Declination sign (J2000)
18 I1 deg DEd Declination (J2000)
20- 21 I2 arcmin DEm Declination (J2000)
23- 27 F5.2 arcsec DEs Declination (J2000)
29- 33 F5.2 mag F220W ? F220W magnitude
35- 38 F4.2 mag e_F220W ? rms uncertainty on F220W
40- 45 F6.3 mag F439W ? F439W magnitude
47- 51 F5.3 mag e_F439W ? rms uncertainty on F439W
53- 58 F6.3 mag F555W ? F555W magnitude
60- 64 F5.3 mag e_F555W ? rms uncertainty on F555W
66- 71 F6.3 mag F675W ? ? F675W magnitude
73- 77 F5.3 mag e_F675W ? rms uncertainty on F675W
79- 84 F6.3 mag F814W ? F814W magnitude
86- 90 F5.3 mag e_F814W ? rms uncertainty on F814W
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Note (1): *: The superstar clusters (SSCs) may be marginally resolved as
discussed in Sect. 3.3.
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History: From electronic AJ version
(End) James Marcout, Patricia Bauer [CDS] 04-Oct-1999