Nuclear Star-forming Structures and the Starburst–Active Galactic Nucleus Connection in Barred Spirals: NGC 3351 and NGC 4303

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

scholarly journals Multiwavelength radio observations of a brightest cluster galaxy at z = 1.71: detection of a modest active galactic nucleus and evidence for extended star formation

2019 ◽  
Vol 487 (1) ◽  
pp. 1210-1217 ◽  
Author(s):  
Ariane Trudeau ◽  
Tracy Webb ◽  
Julie Hlavacek-Larrondo ◽  
Allison Noble ◽  
Marie-Lou Gendron-Marsolais ◽  
...  
Keyword(s):  
Star Formation ◽  
Active Galactic Nucleus ◽  
Spectral Energy Distribution ◽  
Galaxy Cluster ◽  
Far Infrared ◽  
Infrared Emission ◽  
Spectral Energy ◽  
Radio Observations ◽  
Cluster Galaxy ◽  
Star Forming

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.

scholarly journals Host galaxy line diagnostics for the candidate tidal disruption events XMMSL1 J111527.3+180638 and PTF09axc

2021 ◽  
Author(s):  
Anne Inkenhaag ◽  
Peter G Jonker ◽  
Giacomo Cannizzaro ◽  
Daniel Mata Sánchez ◽  
Richard D Saxton
Keyword(s):  
Active Galactic Nucleus ◽  
Seyfert Galaxy ◽  
Emission Lines ◽  
Host Galaxy ◽  
Host Galaxies ◽  
Colour Difference ◽  
Tidal Disruption ◽  
Star Forming ◽  
Extreme Variability ◽  
Dusty Torus

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.

scholarly journals The discovery of the most UV–Ly α luminous star-forming galaxy: a young, dust- and metal-poor starburst with QSO-like luminosities

2020 ◽  
Vol 499 (1) ◽  
pp. L105-L110
Author(s):  
R Marques-Chaves ◽  
J Álvarez-Márquez ◽  
L Colina ◽  
I Pérez-Fournon ◽  
D Schaerer ◽  
...  
Keyword(s):  
Star Formation ◽  
Gravitational Lensing ◽  
Active Galactic Nucleus ◽  
Star Formation Rate ◽  
High Redshift ◽  
Formation Rate ◽  
Star Forming ◽  
Evolutionary Scheme ◽  
Intense Burst

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.

scholarly journals The Galactic center: not an active galactic nucleus

2013 ◽  
Vol 9 (S303) ◽  
pp. 54-58
Author(s):  
Deokkeun An ◽  
Solange V. Ramírez ◽  
Kris Sellgren
Keyword(s):  
Interstellar Medium ◽  
Emission Line ◽  
Active Galactic Nuclei ◽  
Active Galactic Nucleus ◽  
Galactic Center ◽  
Galactic Nuclei ◽  
Extensive Area ◽  
Star Forming ◽  
Nearby Galaxies

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.

scholarly journals THE SINS/zC-SINF SURVEY OFz∼ 2 GALAXY KINEMATICS: EVIDENCE FOR POWERFUL ACTIVE GALACTIC NUCLEUS-DRIVEN NUCLEAR OUTFLOWS IN MASSIVE STAR-FORMING GALAXIES

2014 ◽  
Vol 787 (1) ◽  
pp. 38 ◽  
Author(s):  
N. M. Förster Schreiber ◽  
R. Genzel ◽  
S. F. Newman ◽  
J. D. Kurk ◽  
D. Lutz ◽  
...  
Keyword(s):  
Active Galactic Nucleus ◽  
Massive Star ◽  
Star Forming ◽  
Galaxy Kinematics

scholarly journals The OH Megamaser galaxy IRAS11506−3851: an AGN and star formation revealed by multiwavelength observations

2020 ◽  
Vol 498 (2) ◽  
pp. 2632-2644
Author(s):  
C Hekatelyne ◽  
Rogemar A Riffel ◽  
Thaisa Storchi-Bergmann ◽  
Preeti Kharb ◽  
Andrew Robinson ◽  
...  
Keyword(s):  
Active Galactic Nucleus ◽  
Velocity Dispersion ◽  
Hubble Space Telescope ◽  
Present Stage ◽  
Low Velocity ◽  
Very Large Array ◽  
Star Forming ◽  
Star Forming Regions ◽  
Field Unit ◽  
Integral Field

ABSTRACT We present Gemini Multi-Object Spectrograph (GMOS) Integral Field Unit (IFU), Hubble Space Telescope (HST), and Very Large Array (VLA) observations of the OH Megamaser (OHM) galaxy IRAS 11506−3851. The HST images reveal an isolated spiral galaxy and the combination with the GMOS-IFU flux distributions and VLA data allow us to identify a partial ring of star-forming regions surrounding the nucleus with a radius of ≈ 500 pc. While this ring shows starburst excitation and low velocity dispersion, the region internal to the ring shows higher excitation and velocity dispersion values, with values increasing towards its borders at ≈ 240 pc from the nucleus, resembling a projected bubble. The enhanced excitation and velocity dispersion of this bubble surrounds a 8.5-GHz radio emission structure, supporting its origin in a faint active galactic nucleus (AGN) that is mostly shocking the surrounding gas via a plasma ejection seen in radio at the present stage. This is the fourth of the 5 OHM galaxies we have studied so far (from our sample of 15 OHM) for which GMOS-IFU data indicate the presence of a previously unknown faint AGN at the nucleus, consistent with the hypothesis that OHM galaxies harbour recently triggered AGN.

scholarly journals Vibrationally excited HC3N emission in NGC 1068: tracing the recent star formation in the starburst ring

2021 ◽  
Vol 502 (2) ◽  
pp. 3021-3034
Author(s):  
F Rico-Villas ◽  
J Martín-Pintado ◽  
E González-Alfonso ◽  
V M Rivilla ◽  
S Martín ◽  
...  
Keyword(s):  
Star Formation ◽  
Active Galactic Nucleus ◽  
Column Density ◽  
Local Thermodynamic Equilibrium ◽  
Continuum Emission ◽  
Vibrationally Excited ◽  
Star Forming ◽  
Dust Temperature ◽  
Ngc 1068 ◽  
The Continuum

ABSTRACT Using the ALMA data, we have studied the HC3N and continuum emission in the starburst pseudo-ring (SB pseudo-ring) and the circumnuclear disc (CND) of the SB/active galactic nucleus (AGN) composite galaxy NGC 1068. We have detected emission from vibrationally excited HC3N (HC3N*) only towards one star-forming region of the SB pseudo-ring. Remarkably, HC3N* was not detected towards the CND despite its large HC3N v = 0 column density. From local thermodynamic equilibrium (LTE) and non-LTE modelling of HC3N*, we obtained a dust temperature (Tdust) of ∼250 K and a density $(n_{\text{H}_2}) \text{ of }6\times 10^5$ cm−3 for this star-forming region. The estimated infrared (IR) luminosity of 5.8 × 108 L⊙ is typical of proto-superstar clusters (proto-SSCs) observed in the SB galaxy NGC 253. We use the continuum emissions at 147 and 350 GHz, along with CO and Pa α, to estimate the ages of other 14 SSCs in the SB pseudo-ring. We find the SSCs to be associated with the region connecting the nuclear bar with the SB pseudo-ring, supporting the inflow scenario. For the CND, our analysis yields Tdust ≤ 100 K and $n_{\text{H}_2}\sim (3\!-\!6)\times 10^5$ cm−3. The very different dust temperatures found for the CND and the proto-SSC indicate that, while the dust in the proto-SSC is being efficiently heated from the inside by the radiation from massive protostars, the CND is being heated externally by the AGN, which in the IR optically thin case can only heat the dust to 56 K. We discuss the implications of the non-detection of HC3N* near the luminous AGN in NGC 1068 on the interpretation of the HC3N* emission observed in the SB/AGN composite galaxies NGC 4418 and Arp 220.

scholarly journals A binning-free method reveals a continuous relationship between galaxies’ AGN power and offset from main sequence

2020 ◽  
Vol 495 (1) ◽  
pp. 1392-1402 ◽  
Author(s):  
L P Grimmett ◽  
J R Mullaney ◽  
E P Bernhard ◽  
C M Harrison ◽  
D M Alexander ◽  
...  
Keyword(s):  
Active Galactic Nucleus ◽  
Main Sequence ◽  
Typical Case ◽  
Hierarchical Bayesian Model ◽  
Host Galaxies ◽  
Forming Process ◽  
X Ray ◽  
Star Forming ◽  
The Relationship ◽  
Averaging Techniques

ABSTRACT Studies investigating the relationship between active galactic nucleus (AGN) power and the star formation rates (SFRs) of their host galaxies often rely on averaging techniques – such as stacking – to incorporate information from non-detections. However, averages, and especially means, can be strongly affected by outliers and can therefore give a misleading indication of the ‘typical’ case. Recently, a number of studies have taken a step further by binning their sample in terms of AGN power (approximated by the 2–10 keV luminosity of the AGN), and investigating how the SFR distribution differs between these bins. These bin thresholds are often weakly motivated, and binning implicitly assumes that sources within the same bin have similar (or even identical) properties. In this paper, we investigate whether the distribution of host SFRs – relative to the locus of the star-forming main sequence (i.e. RMS) – changes continuously as a function of AGN power. We achieve this by using a hierarchical Bayesian model that completely removes the need to bin in AGN power. In doing so, we find strong evidence that the RMS distribution changes with 2–10 keV X-ray luminosity. The results suggest that higher X-ray luminosity AGNs have a tighter physical connection to the star-forming process than lower X-ray luminosity AGNs, at least within the 0.8 < z < 1.2 redshift range considered here.

scholarly journals The importance of the diffuse ionized gas for interpreting galaxy spectra

2020 ◽  
Vol 15 (S359) ◽  
pp. 371-380
Author(s):  
Natalia Vale Asari ◽  
Grażyna Stasińska
Keyword(s):  
Star Formation ◽  
Emission Line ◽  
Active Galactic Nucleus ◽  
Early Type ◽  
Late Type ◽  
Chemical Abundances ◽  
Ionized Gas ◽  
Star Forming ◽  
Diffuse Ionized Gas ◽  
Emission Line Spectrum

AbstractDiffuse ionized gas (DIG) in galaxies can be found in early-type galaxies, in bulges of late-type galaxies, in the interarm regions of galaxy disks, and outside the plane of such disks. The emission-line spectrum of the DIG can be confused with that of a weakly active galactic nucleus. It can also bias the inference of chemical abundances and star formation rates in star forming galaxies. We discuss how one can detect and feasibly correct for the DIG contribution in galaxy spectra.

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