ALBERT

Description: In some of the few cases where the line of sight to a Quasi-Stellar Object (QSO) passes near a galaxy, the galaxy redshift is almost identical to an absorption redshift in the spectrum of the QSO. Although these relatively low redshift QSO-galaxy pairs may not be typical of the majority of the narrow heavy-element QSO absorption systems, they provide a direct measure of column densities in the outer parts of galaxies and some limits on the relative abundances of the gas. Observations are presented here of the QSO S4 0248+430 and a nearby anonymous galaxy (Kuhr 1977). The 14 second separation of the line of sight to the QSO (z sub e = 1.316) and the z=0.052 spiral galaxy, (a projected separation of 20 kpc ((h sub o = 50, q sub o = 0)), makes this a particularly suitable pair for probing the extent and content of gas in the galaxy. Low resolution (6A full width half maximum), long slit charge coupled device (CCD) spectra show strong CA II H and K lines in absorption at the redshift of the galaxy (Junkkarinen 1987). Higher resolution spectra showing both Ca II H and K and Na I D1 and D2 in absorption and direct images are reported here.

Description: We present Hubble Space Telescope/Faint Object Spectrograph (HST/FOS) ultraviolet and ground-based optical spectra of the z = 0.692 21 cm absorption system in the quasi-stellar object (QSO) 3CR 286. The strength of the damped Lyman-alpha absorption implies an H I column density, N(H I) approximately 2 x 10(exp 21)/sq cm. We derive a high spin temperature for the H I gas, T(sub s) greater than or approximately equal to 10(exp 3) K, as has been found for other high-redshift 21 cm absorbing systems; at least 80% of the H I is hotter than 1200 K. Curve-of-growth analysis yields Mg(+) and Fe(+) abundances which are approximately 1-2 dex below solar values; the Ca(+) abundance is even lower implying some depletion onto dust grains. The H2 fraction is not high. We speculate that the high inferred T(sub s) for the gas may reflect continuing active star formation at the 5-8 Gyr look-back time to the absorbing galaxy.

Description: We discuss measurements of Ne VIII lambda 774 absorption and the time variability of other lines in the z(sub a) approximately equal z(sub e) absorption system of the z(sub e) = 2.15 QSO UM 675 (0150-203). The C IV lambda 1549 and N V 1240 doublets at z(sub a) = 2.1340 (shifted approximately 1500 km/s from z(sub e) strengthened by a factor of approximately 3 between observations by Sargent, Boksenberg and Steidel (1981 November) and our earliest measurements (1990 November and December). We have no information on changes in other z(sub a) approximately equal z(sub e) absorption lines. Continued monitoring since 1990 November shows no clear changes in any of the absorptions between approximately 1100 and 1640 A rest. The short timescale of the variability (less than or approximately equal to 2.9 yr rest) strongly suggests that the clouds are dense, compact, close to the QSO, and photoionized by the QSO continuum. If the line variability is caused by changes in the ionization, the timescale requires densities greater than approximately 4000/cu cm. Photoionization calculations place the absorbing clouds within approximately 200 pc of the continuum source. The full range of line ionizations (from Ne VIII lambda 774 to C III lambda 977) in optically thin gas (no Lyman limit) implies that the absorbing regions span a factor of more than approximately 10 in distance or approximately 100 in density. Across these regions, the total hydrogen (H I + H II) column ranges from a few times 10(exp 18)/sq cm in the low-ionization gas to approximately 10(exp 20)/sq cm where the Ne VIII doublet forms. The metallicity is roughly solar or higher, with nitrogen possibly more enhanced by factors of a few. The clouds might contribute significant line emission if they nearly envelop the QSO. The presence of highly ionized Ne VIII lambda 774 absorption near the QSO supports recent studies that link z(sub a) approximately equal to z(sub e) systems with X-ray 'wamr absorbers. We show that the Ne VIII absorbing gas would itself produce measurable warm absorption -- characterized by bound-free O VII or O VIII edegs near 0.8 keV -- if the column densities were N(sub H) greater than or approximately equal to 10(exp 21)/sq cm (for solar abundances).

Description: We present results of a study of narrow-line region (NLR) kinematics in Seyfert nuclei. We draw five important conclusions from this work. The scenario in agreement with the greatest number of observational considerations consists of clouds which are accelerated outward with v varies as r(exp 1/2) (i.e., constant force) and n(sub e) varies as 1/r(exp 2)). The clouds start out at the inner NLR radius with n(sub e) approximately = 10(exp 6)/cu cm and with a very large column density (10(exp 23) - 10(exp 24)/sq cm). These clouds are uniformly accelerated from a few tens of km/s to less than or approximately equal to 1000 km/s. When the clouds reach the outer NLR radius, they have n(sub e) approximately = 10(exp 2)/cu cm and a column density of 10(exp 21) - 10(exp 22)/sq cm. The clouds maintain an ionization parameter of about 0.3 throughout the NLR.

Description: Lick Observatory slit spectra of 38 objects which were claimed to have pronounced UV excess and emission lines are presented. Eleven QSOs, four galaxies at z of about 0.1, 22 stars, and one unidentified object with a low S/N spectrum were found. Of 11 objects which Zhan and Chen (1987, 1989) suggested were QSO with z(prism) not greater than 2.8; eight are QSOs. Six of the QSOs show absorption systems, including Q0000+027A with a relatively strong associated C IV absorption system, and Q0008+008 with a damped Ly-alpha system with an H I column density of 10 exp 21/sq cm. The equivalent widths of the Ca II K line, the G band, and the Balmer lines in 10 stars with the best spectra are measured, and metallicities are derived. Seven of them are in the range -2.5 to -1.7, while the others are less metal-poor.

Description: An imaging survey of Ly-alpha disk absorption systems for Ly-alpha emission from the absorbing objects, which are candidate young disk galaxies, has been conducted. Limits are set to the flux in Ly-alpha from these objects of approximately 10 exp -16 ergs/sq cm s (3 sigma), which corresponds to a limit on the star formation rate of 2-7 solar masses/yr, in the absence of dust. This suggests that although disk structures form early, rapid star formation does not occur immediately, or else occurs in episodic fashion.

Description: To investigate the far-UV spectral properties of a QSO and to look for evidence of He I 584 A emission and absorption the Faint Object Spectrograph aboard the HST was used to observed UM 675. Light is detected down to 520 A in the object in the rest frame and limits are set to He I emission, the He I Gunn-Peterson effect at z = 2.148, and Ly-alpha absorption at z roughly 0.5.

Description: Spectrophotometry from 0.46 to 1.3 micron of the peculiar emission-line object V1016 Cyg is presented. The optical region displays a weak continuum underlying the rich emission-line spectrum detailed in past studies. The infrared spectrum consists of prominent emission lines of H I, He I, He II, forbidden Ni, O I, and forbidden S III overlying a strong stellar continuum. The latter displays bands at 0.94 micron and 1.13 micron characteristic of a late-type, oxygen-rich giant as well as an absorption at 1.05 micron which is due to VO. The presence of these molecular features indicates a spectral class of M6 or later for the cool secondary. The reddening of the secondary does not appear to be much different from that of the emission lines. Among the infrared emission features is the rarely seen permitted transition of neutral oxygen at 1.1287 micron. Its presence at a strength comparable to O I 8446 A, together with the absence of O I 13164 A, confirms the result of Strafella that the strong O I lines arise primarily from fluorescent excitation by Ly-beta.

Description: Narrow-band imaging observations are reported which were made in an attempt to detect Ly-alpha emission from high-redshift candidate galaxy disk systems discovered as high column density absorbers of background QSOs. For four systems with z = 2.3-2.8, no emission is detected to a limit of about 10 to the -16th ergs/sq cm/s, corresponding to luminosity limits of about 10 exp 42-43 ergs/s for the material producing the absorption. The inferred Ly-alpha luminosities lie one to two orders of magnitude below estimates of the Ly-alpha luminosities for active star-forming epochs of many prescriptions for galaxy formation and also considerably below measured Ly-alpha luminosities for other candidate young galaxies detected in radio surveys. A limiting star-formation rate in these systems of about 2-7 solar masses/yr is set; the limit may be about 10 times larger with small but observationally allowable amounts of dust.

Description: Measurements of the 10830-A transition of neutral helium are presented for 12 Seyfert 2 galaxies and the emission-line radio galaxy NGC 1275. The observed 10830-A to He I 5876-A ratios for these objects range from 4 to 24, showing that the objects are reddened. For a number of these galaxies, the observed H-alpha/H-beta values exceed that expected with uniform mixing of dust and gas. The results suggest that one or more mechanisms are destroying the 10830-A photons or are depopulating the 2 3S level. Three previously proposed mechanisms to explain this process are evaluated and it is found that all of the proposed mechanisms are lacking.