The Starburst‐Active Galactic Nucleus Connection in Active Galaxies: The MassiveNuclear Star‐Forming Disk in NGC 4303

1999 ◽  
Vol 514 (2) ◽  
pp. 637-647 ◽  
Author(s):  
L. Colina ◽  
S. Arribas
2019 ◽  
Vol 487 (1) ◽  
pp. 1210-1217 ◽  
Author(s):  
Ariane Trudeau ◽  
Tracy Webb ◽  
Julie Hlavacek-Larrondo ◽  
Allison Noble ◽  
Marie-Lou Gendron-Marsolais ◽  
...  

ABSTRACT We present deep, multiwavelength radio observations of SpARCS104922.6 + 564032.5, a z = 1.71 galaxy cluster with a starbursting core. Observations were made with the Karl G. Jansky Very Large Array (JVLA) in three bands: 1–2 GHz, 4–8 GHz, and 8–12 GHz. We detect a radio source coincident with the brightest cluster galaxy (BCG) that has a spectral index of α = 0.44 ± 0.29 and is indicative of emission from an active galactic nucleus. The radio luminosity is consistent with the average luminosity of the lower redshift BCG sample, but the flux densities are 6σ below the predicted values of the star-forming spectral energy distribution based on far infrared data. Our new fit fails to simultaneously describe the far infrared and radio fluxes. This, coupled with the fact that no other bright source is detected in the vicinity of the BCG implies that the star formation region, traced by the infrared emission, is extended or clumpy and not located directly within the BCG. Thus, we suggest that the star-forming core might not be driven by a single major wet merger, but rather by several smaller galaxies stripped of their gas or by a displaced cooling flow, although more data are needed to confirm any of those scenarios.


Author(s):  
Anne Inkenhaag ◽  
Peter G Jonker ◽  
Giacomo Cannizzaro ◽  
Daniel Mata Sánchez ◽  
Richard D Saxton

Abstract We present results of our analysis of spectra of the host galaxies of the candidate Tidal Disruption Events (TDEs) XMMSL1 J111527.3+180638 and PTF09axc to determine the nature of these transients. We subtract the starlight component from the host galaxy spectra to determine the origin of the nuclear emission lines. Using a Baldwin–Phillips–Terlevich (BPT) diagram we conclude that the host galaxy of XMMSL1 J111527.3+180638 is classified as a Seyfert galaxy, suggesting this transient is likely to be caused by (extreme) variability in the active galactic nucleus. We find that the host of PTF09axc falls in the ’star-forming’ region of the BPT-diagram, implying that the transient is a strong TDE candidate. For both galaxies we find a WISE-colour difference of W1 − W2 < 0.8, which means there is no indication of a dusty torus and therefore an active galactic nucleus, seemingly contradicting our BPT finding for the host of XMMSL1 J111527.3+180638. We discuss possible reasons for the discrepant results obtained through the two methods.


2020 ◽  
Vol 499 (1) ◽  
pp. L105-L110
Author(s):  
R Marques-Chaves ◽  
J Álvarez-Márquez ◽  
L Colina ◽  
I Pérez-Fournon ◽  
D Schaerer ◽  
...  

ABSTRACT We report the discovery of BOSS-EUVLG1 at z = 2.469, by far the most luminous, almost un-obscured star-forming galaxy known at any redshift. First classified as a QSO within the Baryon Oscillation Spectroscopic Survey, follow-up observations with the Gran Telescopio Canarias reveal that its large luminosity, MUV ≃ −24.40 and log(LLyα/erg s–1) ≃ 44.0, is due to an intense burst of star formation, and not to an active galactic nucleus or gravitational lensing. BOSS-EUVLG1 is a compact (reff ≃ 1.2 kpc), young (4–5 Myr) starburst with a stellar mass log(M*/M⊙) = 10.0 ± 0.1 and a prodigious star formation rate of ≃1000 M⊙ yr−1. However, it is metal- and dust-poor [12 + log(O/H) = 8.13 ± 0.19, E(B – V) ≃ 0.07, log(LIR/LUV) < −1.2], indicating that we are witnessing the very early phase of an intense starburst that has had no time to enrich the ISM. BOSS-EUVLG1 might represent a short-lived (<100 Myr), yet important phase of star-forming galaxies at high redshift that has been missed in previous surveys. Within a galaxy evolutionary scheme, BOSS-EUVLG1 could likely represent the very initial phases in the evolution of massive quiescent galaxies, even before the dusty star-forming phase.


2013 ◽  
Vol 9 (S303) ◽  
pp. 54-58
Author(s):  
Deokkeun An ◽  
Solange V. Ramírez ◽  
Kris Sellgren

AbstractWe present 10 μm – 35μm Spitzer spectra of the interstellar medium in the central molecular zone (CMZ), the central 210 pc × 60 pc of the Galactic center (GC). We present maps of the CMZ in ionic and H2 emission, covering a more extensive area than earlier spectroscopic surveys in this region. We compare diagnostic line ratios measured in the Spitzer Infrared Nearby Galaxies Survey to our data. Previous work shows that forbidden line ratios can distinguish star-forming galaxies from low-ionization nuclear emission-line regions (LINERs) and active galactic nuclei (AGNs). Our GC line ratios agree with star-forming galaxies and not with LINERs or AGNs.


1996 ◽  
Vol 13 (2) ◽  
pp. 182-182
Author(s):  
Ray Norris

The 3 mm radio continuum emission from active galaxies consists of three components: (1)Synchrotron emission from the active galactic nucleus (AGN), which is over 1 Jy in 3C273 but which is not significant in most of the types of galaxy considered here.(2)Free–free emission from H II regions. The flux of this in a starburst galaxy is typically of the order of 10 mJy and could be imaged with a 3 mm-capable Australia Telescope Compact Array (ATCA).(3)Emission from the tail of the 50–100 K black-body spectrum of the dust. For example, the dust in Arp 220 (redshift of 0·02) at a temperature of 50 K has a flux of 30 mJy at 3 mm. Interestingly, this flux does not decrease substantially with redshift, as the decrease in brightness is compensated for by the redshifting of the steep edge of the blackbody curve, and so infrared-bright galaxies can be studied up to high redshifts with existing instruments.


2014 ◽  
Vol 787 (1) ◽  
pp. 38 ◽  
Author(s):  
N. M. Förster Schreiber ◽  
R. Genzel ◽  
S. F. Newman ◽  
J. D. Kurk ◽  
D. Lutz ◽  
...  

2014 ◽  
Vol 10 (S306) ◽  
pp. 301-303
Author(s):  
Róbert Beck ◽  
László Dobos ◽  
István Csabai

AbstractWe analyse the correlations between continuum properties and emission line equivalent widths of star-forming and narrow-line active galaxies from SDSS. We show that emission line strengths can be predicted reasonably well from PCA coefficients of the stellar continuum using local multiple linear regression. Since upcoming sky surveys will make broadband observations only, theoretical modelling of spectra will be essential to estimate physical properties of galaxies. Combined with stellar population synthesis models, our technique will help generate more accurate model spectra and mock catalogues of galaxies to be used to fit data from new surveys. We also show that, by combining PCA coefficients from the pure continuum and the emission lines, a plausible distinction can be made between weak AGNs and quiescent star-forming galaxies. Our method uses a support vector machine, and allows a more refined separation of active and star-forming galaxies than the empirical curve of Kauffmann et al. (2003).


2002 ◽  
Vol 124 (5) ◽  
pp. 2453-2470 ◽  
Author(s):  
Neal A. Miller ◽  
Frazer N. Owen
Keyword(s):  

1997 ◽  
Vol 484 (1) ◽  
pp. L41-L45 ◽  
Author(s):  
Luis Colina ◽  
María Luisa García Vargas ◽  
J. Miguel Mas-Hesse ◽  
A. Alberdi ◽  
A. Krabbe

Sign in / Sign up

Export Citation Format

Share Document