Is a local bar a good place to find a companion? The near infrared morphology of Maffei 2

Maffei 2 is one of the closest large spiral galaxies lying just beyond the Local Group. It would probably be one of the most heavily studied galaxies in the sky were it not for the approximately 5 magnitudes of visual extinction resulting from its position behind the Galactic plane. It is the site of a burst of nuclear star formation indicated by strong infrared and radii continuum emission. Interferometric maps of CO-12 and CO-13 emission indicate that star formation is associated with a barlike structure consisting of arms of molecular gas that extend from within approximately 50 pc of the dynamical center out to a radius of at least 500 pc. HI maps have shown the galaxy to have an angular extent of approximately 15 feet and a neutral gas mass typical of a large spiral galaxy

The Optical/Near-IR Colors of Broad Absorption Line Quasars, Including the Candidate Radio-Loud BAL Quasar 1556+3517

A candidate radio-loud broad absorption line quasar (RLBAL) has been reported by Becker et al. (1997). We present JHK observations of this object and three other radio-detected BALs taken with the new Michigan-Dartmouth-MIT/Ohio State/Aladdin IR Camera (MOSAIC) on the KPNO 4-meter. The candidate RLBAL 1556+3517 has B-K=6.63, redder than all but one or two known z>1 quasars. This strongly suggests the observed continuum of this quasar is reddened by dust. Even when this extreme reddening is taken into account 1556+3517 is still probably radio-loud, although near-IR spectroscopy to measure its Balmer decrement will be needed to verify this. In addition, since it is a flat-spectrum object, VLBI observations to determine the extent (if any) to which beaming affects our estimate of its radio luminosity will be needed before 1556+3517 can be unequivocally declared a radio-loud BAL. We also use our data and data from the literature to show that optically selected BALs as a class have B-K colors consistent with the observed distribution for optically selected quasars as a whole. Thus there is currently no evidence that the tendency of optically selected BALs to be preferentially radio-intermediate (Hooper, Francis, & Impey 1993) is due to extinction artificially lowering estimated BAL optical luminosities. However, as most quasar surveys, both radio and optical, would be insensitive to a population of reddened radio-quiet BALs, the existence of a large population of reddened BALs similar to 1556+3517 cannot yet be ruled out.Comment: Accepted to ApJ Letters; 10 pages including 1 figure and 2 tables. This version somewhat revised from initial submission, with a better figur

On the Asymmetries of Extended X-ray Emission from Planetary Nebulae

Chandra X-ray Observatory (CXO) images have revealed that the X-ray emitting regions of the molecule-rich young planetary nebulae (PNs) BD+30 3639 (BD+30) and NGC 7027 are much more asymmetric than their optical nebulosities. To evaluate the potential origins of these X-ray asymmetries, we analyze X-ray images of BD+30, NGC 7027, and another planetary nebula resolved by CXO, NGC 6543, within specific energy bands. Image resolution has been optimized by sub-pixel repositioning of individual X-ray events. The resulting subarcsecond-resolution images reveal that the soft (E < 0.7 keV) X-ray emission from BD+30 is more uniform than the harder emission, which is largely confined to the eastern rim of the optical nebula. In contrast, soft X-rays from NGC 7027 are highly localized and this PN is more axially symmetric in harder emission. The broad-band X-ray morphologies of BD+30 and NGC 7027 are highly anticorrelated with their distributions of visual extinction, as determined from high-resolution, space- and ground-based optical and infrared imaging. Hence, it is likely that the observed X-ray asymmetries of these nebulae are due in large part to the effects of nonuniform intranebular extinction. However, the energy-dependent X-ray structures in both nebulae and in NGC 6543 -- which is by far the least dusty and molecule-rich of the three PNs, and displays very uniform intranebular extinction -- suggests that other mechanisms, such as the action of collimated outflows and heat conduction, are also important in determining the detailed X-ray morphologies of young planetary nebulae.Comment: 33 pages, 12 figures; to appear in the Astrophysical Journa