Authors: RUBIN, V. C.; THONNARD, N. T.; FORD, W. K., JR.

Affiliation: AB(Carnegie Institution of Washington, Washington, DC)

Journal: Astronomical Journal, vol. 87, Mar. 1982, p. 477-485. (AJ Homepage)

Publication Date: 03/1982

Category: Astrophysics

Origin: STI NASA/STI

Keywords: GALACTIC ROTATION, OPTICAL MEASUREMENT, RADIO SOURCES (ASTRONOMY), SPIRAL GALAXIES, ABSORPTION SPECTRA, ANGULAR VELOCITY, CENTIMETER WAVES, HYDROGEN, MASS DISTRIBUTION

Bibliographic Code: 1982AJ.....87..477R

Abstract

Optical and 21-cm observations have been made of the small low-luminosity Sb III galaxy NGC 3067. Beyond the nuclear region, rotational velocities rise slowly to 151 km/sec at R = 7.3 kpc, near the limit of the optical disk. The velocity gradient is 5.2 km/sec per kpc. The absorption previously detected along the line of sight to the quasar 3C 232 is located near the minor axis of NGC 3067 at a projected distance of almost two galactic radii. If the absorption arises from gas in circular orbit in the plane of NGC 3067, geometrical considerations require that the rotation velocities continue to rise beyond the optical image, increasing to a velocity near 340 km/sec at R = 40 kpc. Such a velocity implies that 94% of the mass is located beyond the optical image; this mass has a mass/B luminosity ratio greater than 100. Observations at 21 cm at Arecibo have not detected hydrogen clouds at this radial distance, but place an upper limit of 10 to the 7th solar masses for the mass of a single cloud.

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Title: Probing the interstellar medium of external galaxies using quasar absortion lines: The 3C 232/NGC3067 system

Authors: STOCKE, JOHN T.; CASE, JAMES; DONAHUE, MEGAN; SHULL, J. MICHAEL; SNOW, THEODORE P.

Affiliation: Colorado Univ., Boulder. Journal: In NASA, Ames Research Center,

The Interstellar Medium in External Galaxies: Summaries of Contributed Papers p 359-361 (SEE N91-14100 05-90)

Publication Date: 07/1990

Category: Astrophysics

Origin: STI NASA/STI

Keywords: ELECTROMAGNETIC ABSORPTION, GALAXIES, INTERSTELLAR MATTER, LIGHT EMISSION, LINE SPECTRA, QUASARS, SPIRAL GALAXIES, CONTINUUMS, DISTANCE, HALOS, IMAGING TECHNIQUES, IMPINGEMENT, LIGHT TRANSMISSION, MORPHOLOGY, RADIANT FLUX DENSITY, RADIATION DISTRIBUTION, RED SHIFT, SENSITIVITY, ULTRAVIOLET ABSORPTION

Bibliographic Code: 1990imeg.conf..359S

Abstract

Quasar absorption lines offer unique opportunities to probe the interstellar medium of external galaxies. Researchers present new optical and UV absorption line spectroscopy of the quasar 3C232 (z=0.55) revealing new detail in the foreground absorption system due to the bright, spiral galaxy NGC 3067 (cz=1420 km/s). Specifically, the spectra show evidence for two and possibly three separate absorption components in CaII and Na I spanning approx. 150 km/s. The original HI detection of Haschick and Burke (1975) corresponds to the strongest of these metal systems which exhibits doublet ratios consistent with saturation in both CaII and Na I. Due to the recent detection in HI emission of a tidal tail or finger of HI extending from the western edge of NGC 3067 through the position of 3C 232 (Carilli, van Gorkom and Stocke, 1989), the morphology of the HI absorber is now known and is not either a warped disk nor a spherical halo as had been proposed. New deep continuum and H alpha imaging provides a sensitive upper limit on the the ionizing continuum impinging upon this cloud (and thus a limit on the intensity of the extragalactic ionizing radiation field). Together with the observed UV spectrum of 3C 232, the optical emission line ratios and the deep H alpha imaging set a minimum distance between the quasar and the HI cloud disregarding redshift information. This limit strains the non-cosmological redshift interpretation for 3C 232 -- and this quasar is one of the original 5 3C quasars found to be too close to NGC galaxies as if by chance (Burbidge, Burbidge, Solomon and Strittmatter, 1972).