scholarly journals Extreme Emission Line Outflows in the GPS Source 4C 12.50 (PKS 1345+12)

2003 ◽  
Vol 20 (1) ◽  
pp. 25-27 ◽  
Author(s):  
J. Holt ◽  
C. N. Tadhunter ◽  
R. Morganti
Keyword(s):  
High Resolution ◽  
Emission Line ◽  
Radio Source ◽  
Spectral Coverage ◽  
La Palma ◽  
Upper Limit ◽  
Line Region ◽  
The Galaxy ◽  
William Herschel

AbstractWe present high resolution spectra (0.7 Å/pix) of the GPS source 4C 12.50 with large spectral coverage (˜4500 Å) taken with the 4.2 m William Herschel Telescope, La Palma. The slit was aligned along PA 160° to include the nucleus and emission line region to the NW. An asymmetric halo extending 20 kpc NW and 12 kpc SE from the nucleus is clearly seen. At the position of the nucleus we observe unusually broad forbidden emission line components (broadest component: FWHM ˜ 2000 km s−1), blue shifted by up to 2000 km s−1 with respect to the halo of the galaxy and HI absorption. We interpret this as material in outflow. We measure E(B–V) = 1.44 for the broadest, most kinematically disturbed component, corresponding to an actual Hβ flux 130 times brighter than that measured. We calculate an upper limit for the mass of the line emitting gas of order 106 M⊙ for both the intermediate and broad components. Our results are consistent with 4C 12.50 being a young radio source.

scholarly journals Dust Distribution in IRAS Seyfert Galaxies

1994 ◽  
Vol 159 ◽  
pp. 355-355
Author(s):  
M. G. Pastoriza ◽  
Charles Bonatto ◽  
Eduardo Bica ◽  
T. Storchi-Bergmann
Keyword(s):  
Emission Line ◽  
Power Law ◽  
Dust Emission ◽  
Seyfert Galaxies ◽  
Emission Model ◽  
Line Region ◽  
Population Type ◽  
The Galaxy ◽  
Dilution Effects ◽  
Dust Distribution

Observational evidences of dust in the nuclear region of AGNs are substantial (Rudy 1984, ApJ, 284, 33; Jones et al. 1984, PASP, 96, 692). The ionization cones observed in several Seyfert galaxies has been interpreted as shadowing effects by a dust obscuring torus which hides the broad emission line region (BLR) and the central source (Wilson 1992; Storchi-Bergmann, Mulchaey and Wilson 1992, ApJ 395, L73). A large sample of optical and far-IR data for IRAS Seyfert galaxies has been analysed together with dust emission models (Bonatto and Pastoriza 1993), where it has been concluded that the same dust emission model can be applied to both Seyfert types. In order to further study the effects of dust in the spectra of active galactic nuclei, we have obtained spectrophotometry of 21 IRAS Seyfert galaxies in the range 3500–7200 Å and analyse them in conjuction with their IRAS fluxes. The stellar population type is derived from comparisons with normal galaxy templates using dilution effects in the K CaII line as discriminator. For 55% of the sample the population is of late type. For the rest, blue continua due to recent star formation and/or power-law may amount up to 30% at 4000Å. We conclude that the bulge stellar populations of IRAS Seyfert galaxies are similar to those of normal spirals, except that they are more reddened by E(B-V)i ∼ 0.20. Population-subtracted emission line ratios indicate on average stronger reddening for the narrow-line region (E(B-V)l ∼ 0.8. From photoionization models a power-law index for the ionizing continuum α=1.5, and a metallicity larger than solar are obtained. The most luminous IRAS galaxy of the sample (IRAS555) is discuss in detail: in order to be compatible with the observed IRAS fluxes and the optical stellar continuum, the ionizing continuum must be reddened by AV > 10 magnitudes. Consequently a dust structure in this galaxy appears to be increasingly affecting stars and gas towards the galaxy center.

scholarly journals Radio Emission from the Seyfert Galaxy NGC 5548

1982 ◽  
Vol 97 ◽  
pp. 191-192
Author(s):  
J. S. Ulvestad ◽  
A. S. Wilson ◽  
D. G. Wentzel
Keyword(s):  
High Resolution ◽  
Radio Emission ◽  
Radio Source ◽  
Seyfert Galaxy ◽  
Central Component ◽  
The Galaxy ◽  
Ngc 5548

Weak radio emission from the type 1.5 Seyfert galaxy NGC 5548 has been mapped with high resolution at the VLA at both 1465 and 4885 MHz. The galaxy contains the largest (5.9 kpc) triple radio source known in a Seyfert galaxy. The central component of that triple is unresolved (<0.39×0.15 kpc) and has a flatter spectrum than the well-resolved outer lobes. In addition, the field surrounding NGC 5548 and two of the sources in that field have been mapped at 1465 MHz; the field sources are unlikely to be physically associated with NGC 5548.

scholarly journals Bidimensional Spectroscopy with Optical Fibers of Spatially Resolved Emission-Line Regions Around Active Galactic Nuclei

1997 ◽  
Vol 159 ◽  
pp. 339-342
Author(s):  
S. Arribas ◽  
E. Mediavilla ◽  
C. del Burgo ◽  
B. García-Lorenzo
Keyword(s):  
Optical Fiber ◽  
Emission Line ◽  
Active Galactic Nuclei ◽  
Optical Fibers ◽  
Galactic Nuclei ◽  
Spatially Resolved ◽  
La Palma ◽  
William Herschel ◽  
Optical Telescopes

AbstractWe summarize our experience in observing the circumnuclear regions of AGN with the optical-fiber systems that we have developed for the William Herschel and Nordic Optical Telescopes at La Palma.

scholarly journals Is the Broad-Line Region Expanding?

1997 ◽  
Vol 159 ◽  
pp. 222-223
Author(s):  
Kan Liang ◽  
Xiang-Tao He ◽  
Zhong-min Wang ◽  
Jun-Han You
Keyword(s):  
High Resolution ◽  
Emission Line ◽  
High Redshift ◽  
Optical Observations ◽  
Broad Line ◽  
Broad Absorption ◽  
Broad Line Region ◽  
Line Region ◽  
Radial Outflow ◽  
Almost All

We suggest that the broad-line regions (BLRs) of QSOs with broad emissionlines (BALs) are expanding, i.e., the clouds are undergoing radial outflow, as illustrated simply in Fig. 1. At least the following observational facts can be explained: 1.Optical observations show that some moderate and high-redshift QSOs have BALs. The number of these QSOs is about 3–10% of all QSOs (Foltz et al. 1990). One can see in Fig. 2 that very low-redshift QSOs have no BALs.2.Almost all BAL QSOs exhibit zabs < zem.3.High-resolution observations reveal that the widths of the broad absorption lines are narrower than that of the corresponding emission line for all BAL QSOs, i.e. Δλ ab < Δλ em.

scholarly journals Deep Spectroscopy of the Very Extended Ionized Gas of NGC 4388

2004 ◽  
Vol 217 ◽  
pp. 386-388
Author(s):  
Michitoshi Yoshida ◽  
M. Yagi ◽  
S. Okamura ◽  
Y. Ohyama ◽  
N. Kashikawa ◽  
...  
Keyword(s):  
Emission Line ◽  
Virgo Cluster ◽  
Ionized Gas ◽  
Shock Heating ◽  
Line Region ◽  
Systemic Velocity ◽  
Ram Pressure ◽  
The Galaxy ◽  
Solar Abundances ◽  
Extended Emission

We report here the results of deep optical spectroscopy of the very extended emission-line region (VEELR) found serendipitously around the Seyfert 2 galaxy NGC 4388 in the Virgo cluster. The Hα recession velocities of most of the filaments of the region observed are highly blue-shifted with respect to the systemic velocity of the galaxy. The velocity field is complicated, and there seem to be several streams of filaments ranging from ~ −100 km s−1 to ~ −700 km s−1 with respect to the systemic velocity of the galaxy. The emission-line ratios of the VEELR filaments are well explained by power-law photoionization models with solar abundances. In addition to photoionization, shock heating probably contributes to the ionization of the gas. We conclude that the VEELR was formerly the disk gas of NGC 4388, which has been stripped by ram pressure due to the interaction between the hot intra-cluster medium (ICM) and the galaxy.

scholarly journals The Galactic Center

1984 ◽  
Vol 110 ◽  
pp. 265-273
Author(s):  
K. Y. Lo
Keyword(s):  
High Resolution ◽  
Radio Source ◽  
Galactic Center ◽  
Minor Axis ◽  
Ionized Gas ◽  
Nonthermal Radio ◽  
The Galaxy ◽  
First Time ◽  
Source Structure

The center of our Galaxy contains an extremely compact nonthermal radio source. For the first time, elongation in the source structure has been detected. The long axis is nearly aligned with the minor axis of the Galaxy. Recent high resolution observations of the ionized gas within the central 3 parsecs suggest that matter may be falling in towards the center. This has interesting implications on the processes within our Galactic nucleus.

The motion of an emission-line region near the center of the galaxy NGC 4151

2011 ◽  
Vol 55 (9) ◽  
pp. 761-769 ◽  
Author(s):  
E. K. Denissyuk ◽  
R. R. Valiullin ◽  
V. N. Gaisina
Keyword(s):  
Emission Line ◽  
Ngc 4151 ◽  
Line Region ◽  
The Galaxy

scholarly journals A wealth of new planetary nebulae from the IPHAS survey

2011 ◽  
Vol 7 (S283) ◽  
pp. 17-20
Author(s):  
Romano L.M. Corradi ◽  
Laurence Sabin ◽  
Keyword(s):  
Emission Line ◽  
Galactic Plane ◽  
Planetary Nebulae ◽  
Current Status ◽  
Survey Area ◽  
Galactic Disc ◽  
Chemical Gradient ◽  
La Palma ◽  
The Galaxy

AbstractWe report on the current status of the search for planetary nebulae (PNe) in the IPHAS survey, the 1800 square degree H-alpha survey of the Northern Galactic Plane carried out at La Palma Observatory. The first major installment of the “IPHAS Catalogue of Extended Nebulae” is presented. This includes a complete census of emission-line nebulae in 320 square degrees toward the inner regions of the Galaxy. In this area, more than 450 emission nebulae have been catalogued including 100 known PNe, and 155 new IPHAS candidate PNe.A vigorous programme of spectroscopic confirmation of IPHAS candidate PNe over the entire survey area is underway using a number of telescopes worldwide. So far, around one hundred new PNe over the whole IPHAS area have been spectroscopically confirmed. Their main properties, some outstanding examples, as well as the relevance of the IPHAS survey to determine the total PN population in the Galactic disc and its chemical gradient is discussed.

scholarly journals The nature of the radio source Cygnus X

1959 ◽  
Vol 9 ◽  
pp. 339-346 ◽  
Author(s):  
F. D. Drake
Keyword(s):  
High Resolution ◽  
Radio Source ◽  
Optical Observation ◽  
Thermal Spectrum ◽  
The Galaxy ◽  
Spiral Arm

The radio source Cygnus X (IAU 20N4A) has long created interest because of its unusual spectrum, its seemingly extended nature, and its location in a region where we believe we look nearly lengthwise down a spiral arm of the Galaxy. Piddington and Minnett [1] first showed that the source had a thermal spectrum. In a recent paper Davies [2] has concluded that the source is an extremely large extended HII region located in the second spiral arm in Cygnus. The recent construction of large parabolic antennas has made it possible to clarify greatly the nature of Cygnus X; it is the purpose of this paper to give the results of a high-resolution survey of the Cygnus X region, and to report a possibly relevant optical observation.

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