The Environment of Optically Very Luminous Galaxies

2003 ◽  
pp. 123-124
Author(s):  
Alberto Cappi ◽  
Christophe Benoist ◽  
Luiz N. da Costa ◽  
Sophie Maurogordato
Keyword(s):  
Luminous Galaxies

scholarly journals 9.2. Cores or cusps in elliptical galaxies: luminosity or environment?

1998 ◽  
Vol 184 ◽  
pp. 385-386
Author(s):  
Roelof S. de Jong ◽  
Roger L. Davies ◽  
Robert F. Minchin ◽  
John R. Lucey ◽  
James Steel
Keyword(s):  
Elliptical Galaxies ◽  
Steep Slope ◽  
Physical Variable ◽  
Stellar Disk ◽  
Heterogeneous Sample ◽  
Luminous Galaxies ◽  
End Products ◽  
Disk Component ◽  
Ultimate Nature

Two classes of elliptical galaxies are now recognised (Kormendy & Bender 1996). Luminous ellipticals rotate slowly (Davies et al. 1983and tend to have boxy isophotes. Ellipticals fainter than L∗ exhibit an increasing tendency to be rotationally supported and to possess a stellar disk component. This dichotomy led Bender, Burstein & Faber (1992) to suggest that the physical variable that controls the ultimate nature of a forming galaxy is the degree of gaseous dissipation that occurs in the final merger it experiences. Low luminosity systems experience more dissipative mergers which generate high rotation, disky end products. As bigger galaxies are formed, the mergers become increasingly stellar, producing the classical slow rotating ellipticals. They termed this the gas/stellar continuum. This global dichotomy is also reflected in the bimodality of core morphologies of the heterogeneous sample of local ellipticals observed with HST. The low luminosity disky galaxies have ‘hard’ cores with a steep slope in the luminosity profile at small radii, whereas the luminous galaxies have ‘soft’ cores with flat profiles at small radii (e.g. Faber et al. 1997).

scholarly journals Studying the Dynamics of Star Forming and IR Luminous Galaxies with Infrared Spectroscopy

2006 ◽  
pp. 74-84
Author(s):  
Reinhard Genzel ◽  
Linda J. Tacconi ◽  
Marco Barden ◽  
Matthew D. Lehnert ◽  
Dieter Lutz ◽  
...  
Keyword(s):  
Infrared Spectroscopy ◽  
Star Forming ◽  
Luminous Galaxies

scholarly journals Deeply Buried Nuclei in the Infrared-luminous Galaxies NGC 4418 and Arp 220. II. Line Forests at λ = 1.4–0.4 mm and Circumnuclear Gas Observed with ALMA

2021 ◽  
Vol 923 (2) ◽  
pp. 240
Author(s):  
Kazushi Sakamoto ◽  
Sergio Martín ◽  
David J. Wilner ◽  
Susanne Aalto ◽  
Aaron S. Evans ◽  
...  
Keyword(s):  
Galactic Disk ◽  
Vibrationally Excited ◽  
Content Type ◽  
Counter Rotation ◽  
Luminous Galaxies ◽  
Line Absorption ◽  
Type Object ◽  
Upper Level ◽  
Array Imaging ◽  
The Continuum

Abstract We present the line observations in our Atacama Millimeter-Submillimeter Array imaging spectral scan toward three deeply buried nuclei in NGC 4418 and Arp 220. We cover 67 GHz in f rest = 215–697 GHz at about 0.″2 (30, 80 pc) resolution. All the nuclei show dense line forests; we report our initial line identification using 55 species. The line velocities generally indicate gas rotation around each nucleus, tracing nuclear disks of ∼100 pc in size. We confirmed the counter-rotation of the nuclear disks in Arp 220 and that of the nuclear disk and the galactic disk in NGC 4418. While the brightest lines exceed 100 K, most of the major lines and many 13C isotopologues show absorption against even brighter continuum cores of the nuclei. The lines with higher upper-level energies, including those from vibrationally excited molecules, tend to arise from smaller areas, indicating radially varying conditions in these nuclei. The outflows from the two Arp 220 nuclei cause blueshifted line absorption below the continuum level. The absorption mostly has small spatial offsets from the continuum peaks to indicate the outflow orientations. The bipolar outflow from the western nucleus is also imaged in multiple emission lines, showing the extent of ∼1″ (400 pc). Redshifted line absorption against the nucleus of NGC 4418 indicates either an inward gas motion or a small collimated outflow slanted to the nuclear disk. We also resolved some previous confusions due to line blending and misidentification.

scholarly journals NO EVOLUTION IN THE IR–RADIO RELATION FOR IR-LUMINOUS GALAXIES AT z < 2 IN THE COSMOS FIELD

2010 ◽  
Vol 714 (2) ◽  
pp. L190-L195 ◽  
Author(s):  
M. T. Sargent ◽  
E. Schinnerer ◽  
E. Murphy ◽  
C. L. Carilli ◽  
G. Helou ◽  
...  
Keyword(s):  
Luminous Galaxies

The Ratio of H2 to HI Gas in Infrared Luminous Galaxies

1989 ◽  
pp. 603-604
Author(s):  
I. F. Mirabel ◽  
D. B. Sanders
Keyword(s):  
Luminous Galaxies

scholarly journals Observational Evidence for Spectral Evolution of Cluster Galaxies

1988 ◽  
Vol 130 ◽  
pp. 311-319
Author(s):  
Alan Dressler ◽  
James E. Gunn
Keyword(s):  
Galaxy Evolution ◽  
Representative Sample ◽  
Observational Evidence ◽  
Spectral Evolution ◽  
Cluster Galaxies ◽  
Luminous Galaxies ◽  
Detector Technology ◽  
Selection Of

The study of galaxy evolution with large lookback times is dominated by two difficult issues. The first is a technical matter. Even the most luminous galaxies are faint (mr < 19) at significant lookback times (z ≳ 0.5), and so spectrophotometric observations of average galaxies challenge our present telescope and detector technology. The second issue is the selection of objects in an unbiased way in order to assemble a representative sample of galaxies at the remote epoch. It is far too easy to chase only exotic objects whose very peculiarity has brought them to our attention. Though observations of such objects may be fascinating and revealing, they may tell us little about the evolution of an typical galaxy like our own.

scholarly journals Intergalactic HI Clouds

2004 ◽  
Vol 217 ◽  
pp. 26-33
Author(s):  
F. H. Briggs
Keyword(s):  
Star Formation ◽  
Causal Relationship ◽  
Background Radiation ◽  
Low Density ◽  
Luminous Galaxies

Neutral intergalactic clouds are so greatly out numbered by galaxies that their integral HI content is negligible in comparison to that contained in optically luminous galaxies. In fact, no HI cloud that is not associated with a galaxy or grouping of galaxies has yet been identified. This points to a causal relationship that relies on gravitational potentials that bind galaxies also being responsible for confining HI clouds to sufficient density that they can become self-shielding to the ionizing background radiation. Unconfined clouds of low density become ionized, but confined clouds find themselves vulnerable to instability and collapse, leading to star formation.

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