High Optical Luminosity Research Articles

SN 1986E eight years after outburst: a link to SN 1957D?

We report on the optical recovery of SN~1986E 7.1 and 7.9 years after explosion. The spectra are dominated by broad H$\alpha$ and [O~I] $\lambda\lambda$6300,6364 emission lines with a minor contribution from [Ca~II] $\lambda\lambda$7291,7324 and, possibly, [Fe~II] $\lambda$7155. Compared with the spectra of the other recovered SNII, SN1986E shows strong H$\alpha$ luminosity similar to SN~1979C but, in contrast, weak [O~III] emission. So far, among classified SNe, only type II Linears have been recovered a few years past the explosion. The high optical luminosity of Linear SNII at this phase is most likely related to the interaction of the ejecta with the circumstellar wind which is also expected to produce strong radio emission. Therefore radio observations of the remnant of SN~1986E are worth attempting. The circumstellar interaction model predicts that, in the next decade, the strength of the [O~III]/H$\alpha$ emission rapidly increases and [O~III] $\lambda\lambda$4959,5007 should eventually dominate the spectrum. We observed this effect in SN~1957D 30 years after explosion which therefore may represent the normal evolution of SNII with a dense circumstellar medium. The details observed in the spectra of both SNe suggest directions for further refinement of the modelling.

Infrared to x-ray spectral energy distributions of high redshift quasars

view Abstract Citations (60) References (119) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Infrared to X-Ray Spectral Energy Distributions of High Redshift Quasars Bechtold, Jill ; Elvis, Martin ; Fiore, Fabrizio ; Kuhn, Olga ; Cutri, Roc M. ; McDowell, Jonathan C. ; Rieke, Marcia ; Siemiginowska, Aneta ; Wilkes, Belinda J. Abstract We have observed 14 quasars with z > 2.8 with the ROSAT-PSPC, and detected 12 of them, including the z = 4.11 quasar 0000-263. We present the first x-ray spectrum of a radio quiet quasar with z > 3, 1946+768. Its x-ray spectrum is consistent with a power law with spectral index α_E_= 1.8_-1.4_^+2.1^ and no evidence for absorption in excess of the galactic column [α_E_ = 1.00_-0.32_^+0.28^ assuming N_H_ = N_H_(Gal)]. A PSPC hardness ratio is used to constrain the x-ray spectral properties of the quasars for which there were less than 100 photons detected. For the radio quiet quasars, <α_E_> ~ 1.2, if one assumes that there is no absorption in excess of the galactic column. We combine the x-ray data with new ground based optical and near-IR spectrophotometry obtained at the Steward 23 m and Multiple Mirror Telescope, and data from the literature. The spectral energy distributions are compared to those of low redshift objects. For the radio quiet quasars with z > 2.5, the mean <α_ox_>~1.8. This is larger than the mean for quasars with z < 2.5, but consistent with the expected value for quasars with the high optical luminosities of the objects in this sample. For the radio-loud quasars, <α_ox_>~1.4, independent of redshift. This is smaller than the expected value for the optically luminous, high redshift objects in this sample, if they are mostly GHz peaked radio sources and hence comparable to steep-spectrum, compact radio sources at lower redshift. Finally, we compare the spectral energy distributions of two representative objects to the predicted spectrum of a thin accretion disk in the Kerr geometry, and discuss the uncertainties in deriving black hole masses and mass accretion rates. Publication: The Astronomical Journal Pub Date: August 1994 DOI: 10.1086/117076 Bibcode: 1994AJ....108..374B Keywords: Astronomical Spectroscopy; Infrared Astronomy; Quasars; Red Shift; Spectral Energy Distribution; X Ray Spectroscopy; Accretion Disks; Galaxies; Infrared Photometry; Radio Astronomy; Spectrophotometry; X Ray Astronomy; Astrophysics; INFRARED: GALAXIES; RADIO CONTINUUM: GALAXIES; ULTRAVIOLET: GALAXIES; X-RAYS: GALAXIES; QUASARS: EMISSION LINES full text sources ADS | data products SIMBAD (21) NED (21)

A multiwavelength study of the supernova remnant N49 in the Large Magellanic Cloud

The 2.5-m du Pont telescope at Las Campanas, the IUE, and archival high-resolution imager X-ray data from the Einstein Observatory are used to present a detailed imaging and spectroscopic study of the SNR N49 in the LMC. The asymmetry of the optical image and the relatively high X-ray and optical luminosity of this remnant both arise from its interaction with an extended dense cloud to the southeast seen in CO emission. The optical spectra reveal clear evidence of reddening variations on spatial scales as small as about 2 arcsec over the face of the SNR. UV line emission is associated primarily with the bright optical filaments, and the total luminosity of N49 is measured in several optical and UV lines. A combined analysis of IUE and optical spectra indicates a range of radiative shock velocities. Implications for the interstellar medium surrounding N49 are discussed.

The large-scale clustering of radio galaxies

An all-sky sample of radio galaxies at redshifts z ≤ 0.1 is used to study clustering in the Universe on scales up to several hundred Mpc. The two-point correlation function for these galaxies is consistent with their high optical luminosity and location in moderately richy environments: ξ(r) ⇒ (r/11 h −1 Mpc) −1.8 . Direct methods for obtaining the power spectrum of the density field traced by the radio galaxies are discussed, taking into account the selection function of the sample. The results of the power-spectrum analysis indicate that the distribution of radio galaxies is more uniform on very large scales than would be predicted from an extrapolation of the power-law clustering found on small scales

New observations of the variable galaxy Markaryan 509

Markaryan 509 is classified as a type 1 Seyfert galaxy; however, in its compact form and high optical luminosity it resembles a quasar. The bright nucleus is surrounded by a weak structureless envelope with diameter 14 kpc. Measurements of the brightness of Mark. 509 during 1976-1980 are given. The magnitudes of comparison stars around Mark. 509 obtained by different authors are compared. A light curve of Mark. 509 is given.

A Statistical Analysis of the Einstein Normal Galaxy Sample - Part Two - Elliptical and s0 Galaxies

view Abstract Citations (174) References (62) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS A statistical analysis of the Einstein normal galaxy sample. II. Elliptical and SO galaxies. Trinchieri, G. ; Fabbiano, G. Abstract The statistical analysis of a sample of 29 elliptical and S0 field galaxies observed with the Einstein observatory is presented. The data show a correlation between the X-ray and the optical blue luminosity of the form lx ∝ lB1.64 ±0.15. This is significantly steeper than the correlation observed in spiral and irregular galaxies: lx ∝ lB1.08 ±0.07. Several mechanisms for the origin of the X-ray emission in these galaxies have been investigated to explain the observed correlation. Most likely two separate mechanisms are present: thermal radiation from hot gas is required to explain the high-luminosity massive objects (M > 5 x 1011 Msun, Lx, 1041 ergs s -1), while a collection of low-mass binary sources can explain the low-luminosity, low-mass objects. A comparison between radio-loud and radio-quiet galaxies shows that high optical luminosity, or high mass, is required for the onset of nuclear activity, at both radio and X-ray wavelengths. However, this is not sufficient to ensure the presence of active nuclear sources, and a second parameter (at least) is needed. A comparison between radio-loud elliptical galaxies and QS0s shows that the same X-ray emission mechanism that is operating in QSQs could explain the high X-ray luminosity end of the radio-loud galaxy distribution. Publication: The Astrophysical Journal Pub Date: September 1985 DOI: 10.1086/163463 Bibcode: 1985ApJ...296..447T full text sources ADS | data products SIMBAD (32) NED (30) Related Materials (2) Part 1: 1985ApJ...296..430F Part 3: 1987ApJ...312..111F

A search at the millijansky level for milli-arcsecond cores in a complete sample of radio galaxies

A complete sample of 26 extended radio galaxies was observed at 2.29 GHz with the Mark III VLBI system. The fringe spacing was about 3 milli-arcsec, and the detection limit was about 2 millijanskys. Half of the galaxies were found to possess milli-arcsec radio cores. In all but three sources, the nuclear flux density was less than 0.04 of the total flux density. Galaxies with high optical luminosity (less than -21.2) were more likely than less luminous galaxies to contain a detectable milliparcsec radio core (69 percent vs. 20 percent). For objects with arcsec cores, 80 percent were found to have a milli-arcsec core, even though the milli-arcsec object did not always contribute the greater part of the arcsec flux density.

Spectroscopy of the nebulosity around eight high-luminosity QSOs

view Abstract Citations (131) References (28) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Spectroscopy of the nebulosity around eight high-luminosity QSOs. Boroson, T. A. ; Oke, J. B. Abstract Spectra between 5000 and 9500 A have been obtained for the nebulosities around eight QSOs. These QSOs are all radio sources and were chosen for their high optical luminosities. The spectra of the nebulosities show either blue continua and strong emission lines, or red continua with weak or no emission lines. It is suggested that all the continua arise from stars, although only one object, 3C 48, shows definite stellar absorption lines. Those objects showing strong emission lines require several times 100 million solar masses of gas within the underlying galaxy. The separation into the two groups correlates with many other properties of the QSOs, including radio morphology and spectral index, Fe II emission, and Balmer line width. Publication: The Astrophysical Journal Pub Date: June 1984 DOI: 10.1086/162126 Bibcode: 1984ApJ...281..535B Keywords: Astronomical Spectroscopy; Interstellar Matter; Luminous Intensity; Optical Emission Spectroscopy; Quasars; Balmer Series; Emission Spectra; Interstellar Gas; Line Spectra; Spectral Energy Distribution; Visible Spectrum; Astrophysics full text sources ADS | data products SIMBAD (8) NED (8)

Q 0932+501 — Another Bright Quasar with Broad Absorption Features

AbstractQ 0932 + 501 is a radio quiet quasar with broad absorption troughs of CIV, SiIV and NV, very similar to PHL 5200. In the troughs at least two, possibly three comparatively sharp‐lined emission systems are seen. It is speculated that these lines possibly originate in shocks at the boundary between the outstreaming gas and the intergalactic medium. The existence of emission lines from the central source is uncertain, week and broad traces of them are possibly present. – The fact is stressed that all hitherto known quasars with broad absorptions are radio quiet and of high optical luminosity.