The Optical Spectroscopic Properties of Seyfert 1 Galaxies Selected from Ultraluminous Infrared Galaxies

The ultraluminous infrared galaxies (ULIRGs) are strong interacting or merging galaxies. Statistical study shows that about ten percent of ULIRGs are QSOs or Seyfert 1 galaxies, and high–resolution HST images suggest that they are likely to be at the post merger stage. We investigate the optical spectroscopic properties for a complete sample of 28 QSOs/Seyfert 1s selected mainly from the IRAS galaxy redshift survey QDOT and 1.2 Jy catalogs. The optical spectra were obtained with the 2.16 m optical telescope of the Beijing Astronomical Observatory between October 1998 and the end of 1999. Statistical results for both continuum and emission lines show the following:1. Most of our sample galaxies are strong or extremely strong FeII emitters with a ratio of FeII/Hβ larger than 2. There also exists an anti-correlation of the ratio of FeII/Hβ with EW(OIII) and FWHM(Hβ).2. We fit the continuum for all sample galaxies. Aside from a few objects which could be fitted well by a power-law model, the continuum for most sample Seyfert 1 galaxies can be fitted well by a blackbody model or by composites of power–law and blackbody models. For Seyfert 1 galaxies which fit a power–law, E(B-V) is small and in the range of optically selected Seyfert 1 galaxies. However, for Seyfert 1 galaxies fitting a blackbody model, the temperature increases as E(B-V) increases. This is strong observational evidence to support the evolutionary scenario from starbursts to optical QSOs/Seyfert 1s.3. We also discuss the possible mechanism for strong FeII emission from the point of view of evolution of mergers to AGNs.

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Infrared Power‐Law Galaxies in the Chandra Deep Field–South: Active Galactic Nuclei and Ultraluminous Infrared Galaxies

The Astrophysical Journal ◽

10.1086/499800 ◽

2006 ◽

Vol 640 (1) ◽

pp. 167-184 ◽

Cited By ~ 184

Author(s):

A. Alonso‐Herrero ◽

P. G. Perez‐Gonzalez ◽

D. M. Alexander ◽

G. H. Rieke ◽

D. Rigopoulou ◽

...

Keyword(s):

Active Galactic Nuclei ◽

Power Law ◽

Galactic Nuclei ◽

Infrared Galaxies ◽

Ultraluminous Infrared Galaxies

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Merging Galaxies with Multiple Nuclei from HST ULIRGs Snapshot Survey

Symposium - International Astronomical Union ◽

10.1017/s007418090022086x ◽

2001 ◽

Vol 205 ◽

pp. 172-175

Author(s):

J. Cui ◽

X.-Y. Xia ◽

Z.-G. Deng ◽

S. Mao ◽

Z.-L. Zou

Keyword(s):

Active Galactic Nuclei ◽

Galactic Nuclei ◽

Infrared Galaxies ◽

Merging Galaxies ◽

Ultraluminous Infrared Galaxies ◽

Single Nucleus ◽

High Fraction ◽

Survey Sample ◽

Statistical Studies ◽

Photometric Measurements

We perform photometric measurements on a large HST snapshot imaging survey sample of 97 ultraluminous infrared galaxies (ULIRGs). We classify all the sources into three categories with multiple, double and single nucleus/nuclei, mainly based on a quantitative criterion of I-band luminosity. The resultant fractions of multiple, double and single nucleus/nuclei ULIRGs are 18%, 39% and 43%, respectively. This supports the multiple merger scenario as a possible origin of ULIRGs, in addition to the commonly-accepted pair merger model. Further statistical studies indicate that the fraction of AGN increases from multiple (18%) to double (39%) and then to single (43%) nucleus/nuclei ULIRGs. For the single nucleus category, there is a high luminosity tail in the luminosity distribution, which corresponds to a Seyfert 1/QSO excess. This supports the statement that active galactic nuclei tend to appear at final merging stage. For multiple and double mergers, we also find a considerably high fraction of very close nucleus pairs (e.g., 2/3 for those separated by less than 5 kpc). This strengthens the conclusion that systems at late merging phase preferentially host ULIRGs.

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ChandraObservations of Ultraluminous Infrared Galaxies: Extended Hot Gaseous Halos in Merging Galaxies

The Astrophysical Journal ◽

10.1086/422164 ◽

2004 ◽

Vol 611 (1) ◽

pp. 208-219 ◽

Cited By ~ 21

Author(s):

Z. Y. Huo ◽

X. Y. Xia ◽

S. J. Xue ◽

S. Mao ◽

Z. G. Deng

Keyword(s):

Infrared Galaxies ◽

Merging Galaxies ◽

Ultraluminous Infrared Galaxies

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A Galaxy Merging Sequence Traced by X-rays

Symposium - International Astronomical Union ◽

10.1017/s0074180900198122 ◽

2004 ◽

Vol 217 ◽

pp. 430-431

Author(s):

Yu Gao ◽

Q. Daniel Wang ◽

Ted A. Markowsky

Keyword(s):

Numerical Simulations ◽

X Rays ◽

Galaxy Mergers ◽

Infrared Galaxies ◽

Merging Galaxies ◽

X Ray ◽

Luminous Infrared Galaxies ◽

Optical Images ◽

Ultraluminous Infrared Galaxies

We are studying a sample of nearly 20 nearby (cz≲13,000 km s−1) IR-luminous interacting/merging galaxies observed with the ACIS in the Chandra archive (e.g., Gao et al. 2003; Ptak et al. 2003). Most galaxies in the sample are luminous infrared galaxies (LIGs) and nearly half of them are ultraluminous infrared galaxies (ULIGs) with bolometric luminosities comparable to QSOs. Based on multiwavelength data and numerical simulations of gas-rich galaxy mergers, we have attempted to arrange them in a merger sequence perspective and compared their broadband X-ray emission here with the optical images (mostly DSS).

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Dynamical Properties of Ultraluminous Infrared Galaxies. II. Traces of Dynamical Evolution and End Products of Local Ultraluminous Mergers

The Astrophysical Journal ◽

10.1086/507834 ◽

2006 ◽

Vol 651 (2) ◽

pp. 835-852 ◽

Cited By ~ 103

Author(s):

K. M. Dasyra ◽

L. J. Tacconi ◽

R. I. Davies ◽

T. Naab ◽

R. Genzel ◽

...

Keyword(s):

Dynamical Evolution ◽

Infrared Galaxies ◽

End Products ◽

Ultraluminous Infrared Galaxies ◽

Dynamical Properties

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Matrix integrals & finite holography

Journal of High Energy Physics ◽

10.1007/jhep06(2021)120 ◽

2021 ◽

Vol 2021 (6) ◽

Author(s):

Dionysios Anninos ◽

Beatrix Mühlmann

Keyword(s):

Critical Exponents ◽

Continuum Theory ◽

Point Of View ◽

Leading Order ◽

Minimal Models ◽

Point Evaluation ◽

Brst Cohomology ◽

Matrix Integrals ◽

The Matrix ◽

The Continuum

Abstract We explore the conjectured duality between a class of large N matrix integrals, known as multicritical matrix integrals (MMI), and the series (2m − 1, 2) of non-unitary minimal models on a fluctuating background. We match the critical exponents of the leading order planar expansion of MMI, to those of the continuum theory on an S2 topology. From the MMI perspective this is done both through a multi-vertex diagrammatic expansion, thereby revealing novel combinatorial expressions, as well as through a systematic saddle point evaluation of the matrix integral as a function of its parameters. From the continuum point of view the corresponding critical exponents are obtained upon computing the partition function in the presence of a given conformal primary. Further to this, we elaborate on a Hilbert space of the continuum theory, and the putative finiteness thereof, on both an S2 and a T2 topology using BRST cohomology considerations. Matrix integrals support this finiteness.

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