A Nearly Symmetric Double-Image Gravitational Lens

We report the discovery of a new double-image gravitational lens, resulting from our search for lenses in the southern sky. Radio source PMN J2004-1349 is composed of two compact components separated by 1.″13 in VLA, MERLIN, and VLBA images. The components have a flux ratio of 1:1 at radio frequencies ranging from 5 to 22.5 GHz. The I-band optical counterpart is also an equal double, with roughly the same separation and position angle as the radio double. Upon subtraction of the components from the I-band image, we identify a dim pattern of residuals as the lens galaxy. While the present observations are sufficient to establish that PMN J2004-1349 is a gravitational lens, additional information will be necessary (such as the redshifts of the galaxy and quasar and precise astrometry and photometry of the lens galaxy) before constructing detailed mass models.

[1]  R. Webster,et al.  Binary quasars , 2000, astro-ph/0008069.

[2]  J. Lehár,et al.  PMN J1838−3427: A New Gravitationally Lensed Quasar , 2000, astro-ph/0008036.

[3]  C. Keeton,et al.  Analytic Time Delays and H0 Estimates for Gravitational Lenses , 2000, astro-ph/0004069.

[4]  J. Lehár,et al.  Hubble Space Telescope Observations of 10 Two-Image Gravitational Lenses , 1999 .

[5]  S. Myers.  Scaling the universe: gravitational lenses and the Hubble constant. , 1999, Proceedings of the National Academy of Sciences of the United States of America.

[6]  D. Schlegel,et al.  Maps of Dust Infrared Emission for Use in Estimation of Reddening and Cosmic Microwave Background Radiation Foregrounds , 1998 .

[7]  L. Koopmans,et al.  The edge-on spiral gravitational lens B1600 + 434 , 1998, astro-ph/9801186.

[8]  C. Kochanek,et al.  Limits on Cosmological Models from Radio-selected Gravitational Lenses , 1997, astro-ph/9707032.

[9]  D. Schlegel,et al.  Maps of Dust IR Emission for Use in Estimation of Reddening and CMBR Foregrounds , 1997, astro-ph/9710327.

[10]  C. Kochanek,et al.  Why Quasar Pairs are Binary Quasars and Not Gravitational Lenses , 1997, astro-ph/9710165.

[11]  C. Kochanek,et al.  The Optical Properties of Gravitational Lens Galaxies as a Probe of Galaxy Structure and Evolution , 1997, astro-ph/9708161.

[12]  J. Primack,et al.  Inclination Effects in Spiral Galaxy Gravitational Lensing , 1997, astro-ph/9701110.

[13]  C. Kochanek,et al.  Shear and Ellipticity in Gravitational Lenses , 1996, astro-ph/9610163.

[14]  C. Kochanek.  Is there a cosmological constant , 1995, astro-ph/9510077.

[15]  E. Greisen,et al.  The NRAO VLA Sky Survey , 1996 .

[16]  R. Ekers,et al.  The Parkes-MIT-NRAO (PMN) surveys. 3: Source catalog for the tropical survey (-29 deg less than delta less than -9 deg .5) , 1994 .

[17]  Alan E. Wright,et al.  The Parkes-MIT-NRAO (PMN) surveys. I: The 4850 MHz surveys and data reduction , 1993 .

[18]  Arlo U. Landolt,et al.  UBVRI Photometric Standard Stars in the Magnitude Range 11 , 1992 .

[19]  M. Fukugita,et al.  Statistical properties of gravitational lenses with a nonzero cosmological constant , 1992 .

[20]  E. Turner.  Gravitational lensing limits on the cosmological constant in a flat universe , 1990 .

[21]  J. Lehár,et al.  Faint radio sources and gravitational lensing , 1990 .

[22]  M. Irwin,et al.  Photometric variations in the Q2237 + 0305 system - First detection of a microlensing event , 1989 .

[23]  S. Refsdal.  On the possibility of determining Hubble's parameter and the masses of galaxies from the gravitational lens effect , 1964 .