PLANETARY NEBULAE IN THE ELLIPTICAL GALAXY NGC 4649 (M 60): KINEMATICS AND DISTANCE REDETERMINATION

Journal Article · Wed Jul 20 04:00:00 EDT 2011 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/736/1/65· OSTI ID:21578308

Teodorescu, A M; Mendez, R H ^[1]; Bernardi, F ^[2]; Thomas, J; Das, P; Gerhard, O ^[3]

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1. Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States)
2. Dipartimento di Matematica, Universita di Pisa, Largo B. Pontecorvo 5, 56127 Pisa (Italy)
3. Max Planck Institut fuer Extraterrestrische Physik, P.O. Box 1603, D-85740 Garching bei Muenchen (Germany)

Using a slitless spectroscopy method with (1) the 8.2 m Subaru telescope and its FOCAS Cassegrain spectrograph and (2) the ESO Very Large Telescope unit 1 (Antu) and its FORS2 Cassegrain spectrograph, we have detected 326 planetary nebulae (PNs) in the giant Virgo elliptical galaxy NGC 4649 (M 60) and measured their radial velocities. After rejecting some PNs more likely to belong to the companion galaxy NGC 4647, we have built a catalog with kinematic information for 298 PNs in M 60. Using these radial velocities, we have concluded that they support the presence of a dark matter halo around M 60. Based on an isotropic, two-component Hernquist model, we estimate the dark matter halo mass within 3R{sub e} to be 4 x 10{sup 11} M{sub sun}, which is almost one-half of the total mass of about 10{sup 12} M{sub sun} within 3R{sub e}. This total mass is similar to that estimated from globular cluster, XMM-Newton, and Chandra observations. The dark matter becomes dominant outside. More detailed dynamical modeling of the PN data is being published in a companion paper. We have also measured the m(5007) magnitudes of many of these PNs and built a statistically complete sample of 218 PNs. The resulting PN luminosity function (PNLF) was used to estimate a distance modulus of 30.7 {+-} 0.2 mag, equivalent to 14 {+-} 1 Mpc. This confirms an earlier PNLF distance measurement based on a much smaller sample. The PNLF distance modulus remains smaller than the surface brightness fluctuation distance modulus by 0.4 mag.

• OSTI ID: 21578308
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 1 Vol. 736; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
DISTANCE
FUNCTIONS
GALAXIES
LUMINOSITY
MASS
MATTER
NEBULAE
NONLUMINOUS MATTER
OPTICAL PROPERTIES
PHYSICAL PROPERTIES
PLANETARY NEBULAE
RADIAL VELOCITY
SIMULATION
VELOCITY