2014A&A...572A..64M


C.D.S. - SIMBAD4 rel 1.7 - 2020.07.14CEST19:55:10

2014A&A...572A..64M - Astronomy and Astrophysics, volume 572A, 64-64 (2014/12-1)

Evidence for photometric contamination in key observations of Cepheids in the benchmark galaxy IC 1613.

MAJAESS D., TURNER D.G., GIEREN W. and NGEOW C.

Abstract (from CDS):

This study helps increase awareness of the pernicious effects of photometric contamination (crowding/blending), since it can propagate an undesirable systematic offset into the cosmic distance scale. The latest Galactic Cepheid Wesenheit (VIc) and Spitzer calibrations were employed to establish distances for classical Cepheids in IC 1613 and NGC 6822, thus enabling the impact of photometric contamination to be assessed in concert with metallicity. Distances (WVIc, [3.6]) for Cepheids in IC 1613 exhibit a galactocentric dependence, whereby Cepheids near the core appear (spuriously) too bright (rg<2'). That effect is attributed to photometric contamination from neighboring (unresolved) stars, since the stellar density and surface brightness may increase with decreasing galactocentric distance. The impact is relatively indiscernible for a comparison sample of Cepheids occupying NGC 6822, a result that is partly attributable to that sample being nearer than the metal-poor galaxy IC 1613. WVIc and [3.6] distances for relatively uncontaminated Cepheids in each galaxy are comparable, thus confirming that period-magnitude relations (Leavitt Law) in those bands are relatively insensitive to metallicity (Δ[Fe/H]≃1).

Abstract Copyright:

Journal keyword(s): stars: variables: Cepheids

Simbad objects: 11

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Number of rows : 11

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2020
#notes
1 NAME SMC G 00 52 38.0 -72 48 01   2.79 2.2     ~ 9446 1
2 IC 1613 GiC 01 04 54.2 +02 08 00   10.42 10.01 9.77   ~ 1107 2
3 V* SU Cas cC* 02 51 58.7508894403 +68 53 18.601570075 6.92 6.44 5.80     F5.5III+ 407 1
4 NAME Magellanic Clouds GrG 03 00 -71.0           ~ 5669 1
5 NAME LMC G 05 23 34.6 -69 45 22     0.4     ~ 14832 1
6 V* TW Nor cC* 16 04 55.2266686530 -51 57 12.652767620   13.67 11.17     ~ 139 0
7 V* QZ Nor cC* 16 11 20.4661902809 -54 21 14.826048900 10.08 9.53 8.71 8.66   G1Iab 116 0
8 V* V340 Nor cC* 16 13 17.3998357878 -54 14 05.588347830   9.61 8.47 8.83   G2Iab 134 0
9 NGC 6822 G 19 44 56.199 -14 47 51.29   18 8.1     ~ 1430 0
10 V* CF Cas cC* 23 58 17.9757306390 +61 13 15.821709555   12.72 10.80   9.700 F8Ibv 214 0
11 NAME Local Group GrG ~ ~           ~ 6973 0

    Equat.    Gal    SGal    Ecl

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2020.07.14-19:55:10

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