2001A&A...366...54M


Query : 2001A&A...366...54M

2001A&A...366...54M - Astronomy and Astrophysics, volume 366, 54-61 (2001/1-4)

Anomalous surface brightness fluctuations in NGC 4489.

MEI S., SILVA D.R. and QUINN P.J.

Abstract (from CDS):

Anomalously high K-band surface brightness fluctuations (SBF) have been reported in NGC 4489 by Pahre & Mould (1994ApJ...433..567P), Jensen et al. (1996ApJ...468..519J) and Jensen et al. (1998ApJ...505..111J). However, these conclusions were uncertain because of relatively low signal-to-noise data. New high signal-to-noise data for NGC 4489 have been obtained at the NOAO/KPNO 2.1 m and the ESO/La Silla 3.5 m NTT telescopes. Adopting the I-band SBF distance modulus determined by Tonry et al. (2001ApJ...546..681T) and the <M>I versus (V-I) calibration of Tonry et al. (2000ApJ...530..625T), a value of <M>K=-6.29±0.10mag was derived. Relative to the average empirical <M>K derived for giant ellipticals by Jensen et al. (1998ApJ...505..111J) (<M>K=-5.61±0.12mag), the detection of an anomalous K-band SBF in NGC 4489 is confirmed at the two sigma level. Such anomalous fluctuations could be caused by an extended giant branch, consisting of either intermediate-age AGB stars above the tip of the first-ascent giant branch or high-metallicity first-ascent giants, or by lack of a full understanding of the K-band SBF calibration. This result raises questions about the accuracy of K-band SBF distance measurements for elliptical galaxies with unknown stellar composition and underscores the need for <M>K measurements over a larger range of color and luminosity.

Abstract Copyright:

Journal keyword(s): galaxies: distances and redshift - individual: NGC 4489

Simbad objects: 5

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Number of rows : 5
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2022
#notes
1 M 32 IG 00 42 41.825 +40 51 54.61 9.51 9.03 8.08     ~ 2095 2
2 M 105 LIN 10 47 49.600 +12 34 53.87   10.56 9.76 9.12 8.18 ~ 1424 0
3 NGC 3780 LIN 11 39 22.3564409496 +56 16 14.409578892   12.2       ~ 113 0
4 NGC 4365 GiG 12 24 28.228 +07 19 03.07   11.5       ~ 820 0
5 NGC 4489 GiG 12 30 52.2472748976 +16 45 31.866359004   13.2       ~ 247 0

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2022.08.17-13:11:02

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