THE ARAUCARIA PROJECT: THE DISTANCE TO THE SCULPTOR GALAXY NGC 247 FROM NEAR-INFRARED PHOTOMETRY OF CEPHEID VARIABLES

Journal Article · Sat Aug 01 04:00:00 EDT 2009 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/700/2/1141; COUNTRY OF INPUT: INTERNATIONAL ATOMIC ENERGY AGENCY (IAEA)· OSTI ID:21313798

Gieren, Wolfgang; Pietrzynski, Grzegorz; Szewczyk, Olaf ^[1]; Soszynski, Igor ^[2]; Bresolin, Fabio; Kudritzki, Rolf-Peter; Urbaneja, Miguel A ^[3]; Storm, Jesper ^[4]; Minniti, Dante ^[5]; GarcIa-Varela, Alejandro ^[6]

---

1. Universidad de Concepcion, Departamento de Astronomia, Casilla 160-C, Concepcion (Chile)
2. Warsaw University Observatory, Al. Ujazdowskie 4, 00-478, Warsaw (Poland)
3. Institute for Astronomy, University of Hawaii at Manoa, 2680 Woodlawn Drive, Honolulu HI 96822 (United States)
4. Astrophysikalisches Institut Potsdam, An der Sternwarte 16, D-14482 Potsdam (Germany)
5. Departamento de Astronomia y Astrofisica, Pontificia Universidad Catolica de Chile, Casilla 306, Santiago 22 (Chile)
6. Universidad de los Andes, Departamento de Fisica, Bogota (Colombia)

We have obtained deep near-infrared images in J and K filters of four fields in the Sculptor Group spiral galaxy NGC 247 with the ESO VLT and Infrared Spectrometer and Array Camera. For a sample of 10 Cepheids in these fields, previously discovered by GarcIa-Varela et al. from optical wide-field images, we have determined mean J and K magnitudes and have constructed the period-luminosity (PL) relations in these bands. Using the near-infrared PL relations together with those in the optical V and I bands, we have determined a true distance modulus for NGC 247 of 27.64 mag, with a random uncertainty of {+-}2% and a systematic uncertainty of {approx}4% which is dominated by the effect of unresolved stars on the Cepheid photometry. The mean reddening affecting the NGC 247 Cepheids of E(B - V) = 0.18 {+-} 0.02 mag is mostly produced in the host galaxy itself and is significantly higher than what was found in the previous optical Cepheid studies in NGC 247 of our own group, and Madore et al., leading to a 7% decrease in the previous optical Cepheid distance. As in other studies of our project, the distance modulus of NGC 247 we report is tied to an assumed Large Magellanic Cloud distance modulus of 18.50. Comparison with other distance measurements to NGC 247 shows that the present IR-based Cepheid distance is the most accurate among these determinations. With a distance of 3.4 Mpc, NGC 247 is about 1.5 Mpc more distant than NGC 55 and NGC 300, two other Sculptor Group spirals analyzed before with the same technique by our group.

• OSTI ID: 21313798
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 2 Vol. 700; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

99 GENERAL AND MISCELLANEOUS
CAMERAS
CEPHEIDS
DISTANCE
FILTERS
INFRARED SPECTROMETERS
LUMINOSITY
MAGELLANIC CLOUDS
PHOTOMETRY
RANDOMNESS
RED SHIFT