scholarly journals uGMRT detection of associated H i 21-cm absorption at z ≈ 3.5

2020 ◽  
Vol 500 (1) ◽  
pp. 998-1002
Author(s):  
J N H S Aditya ◽  
Regina Jorgenson ◽  
Vishal Joshi ◽  
Veeresh Singh ◽  
Tao An ◽  
...  
Keyword(s):  
Equivalent Width ◽  
Active Galactic Nucleus ◽  
Optical Spectrum ◽  
Significant Contribution ◽  
Neutral Hydrogen ◽  
Emission Lines ◽  
Host Galaxy ◽  
Width Ratio ◽  
Host Galaxies ◽  
Using Data

ABSTRACT We report a uGMRT (upgraded Giant Metrewave Radio Telescope) detection of H i 21-cm absorption associated with the radio source 8C 0604+728, at z = 3.52965. The source is at the highest redshift at which associated H i 21-cm absorption has been discovered to date, surpassing earlier known absorber at z ≈ 3.39. We estimate ultraviolet luminosities of $\rm (3.2 \pm 0.1) \times 10^{23}$ and $\rm (6.2 \pm 0.2)\times 10^{23}~W~Hz^{-1}$, and ionizing photon rates of $\rm (1.8 \pm 0.1) \times 10^{56}$ and $\rm (5.0 \pm 0.1) \times 10^{56}~s^{-1}$, using data at different epochs; the source shows year-scale variability in both its luminosity and photon rate. The luminosity and photon rate at later epochs are ≈6.2 and ≈1.7 times higher than thresholds suggested in the literature above which all the neutral hydrogen in the active galactic nucleus (AGN) host galaxy is expected to be ionized. The detection demonstrates that neutral hydrogen can survive in the host galaxies of AGNs with high ultraviolet luminosities. We estimate a high equivalent width ratio of 15.2 for the Lyman-α (Ly α) and He ii emission lines detected in the optical spectrum, which is consistent with AGN photoionization models. However, a significant contribution from young stellar populations to the excess Ly α flux cannot be ruled out.

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 redshift and the host galaxy of the neutrino candidate 4FGL J0955.1+3551 (3HSP J095507.9+355101)

2020 ◽  
Vol 495 (1) ◽  
pp. L108-L111
Author(s):  
Simona Paiano ◽  
Renato Falomo ◽  
Paolo Padovani ◽  
Paolo Giommi ◽  
Adriana Gargiulo ◽  
...  
Keyword(s):  
Equivalent Width ◽  
Absolute Magnitude ◽  
Emission Lines ◽  
Absorption Lines ◽  
Host Galaxy ◽  
Source Image ◽  
Host Galaxies ◽  
Upper Limit ◽  
Bl Lac ◽  
Bl Lacs

ABSTRACT The BL Lac object 4FGL J0955.1+3551 has been suggested as a possible source of ultra-energetic neutrinos detected by the IceCube observatory. The target was observed in 2020 January at the Large Binocular Telescope. Our spectroscopy (4100–8500 Å) yields a firm redshift z = 0.557 as deduced by the absorption lines of the host galaxy. The upper limit of the minimum equivalent width on emission lines is ∼0.3 Å. From the source image, we are able to resolve the host galaxy for which we measure an absolute magnitude M(R) = −22.9 and Re = 8 kpc, which are values which are typical of the host galaxies of BL Lacs.

Extended He ii 4686 emission in Markarian 387

2020 ◽  
Vol 498 (3) ◽  
pp. 4550-4561
Author(s):  
QiQi Wang ◽  
Richard G Kron
Keyword(s):  
Interstellar Medium ◽  
Equivalent Width ◽  
Active Galactic Nucleus ◽  
Neutral Hydrogen ◽  
Far Infrared ◽  
Host Galaxy ◽  
High Ionization ◽  
Nearby Galaxies ◽  
Exterior Regions ◽  
Hydrogen Mass

ABSTRACT In order to explore the effect of an active galactic nucleus (AGN) on the interstellar medium of its host galaxy, we selected a promising case for study, Markarian 387 (Mrk 387), based on the strength of its extended He ii 4686 emission, a high-ionization line that can be excited by a hard source of radiation. We use area-resolved spectroscopy from the Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) survey and the availability of additional multiwavelength data. Besides harbouring an obscured AGN and the extended He ii 4686 emission, Mrk 387 has a number of other unusual properties, including a high far-infrared luminosity, a low neutral hydrogen mass compared to the stellar mass, a high Hα luminosity and high Hα equivalent width throughout the disc, and strong He i 5876 in the exterior regions. He ii 4686 and [O iii] 5008 extend with a bilateral morphology beyond 6 kpc from the nucleus. We interpret this emission as due to photoionization from the central source, where the interstellar medium must be sufficiently porous to allow the ionizing flux to reach these relatively distant regions.

scholarly journals Statistical Properties of Gamma-Ray Burst Host Galaxies

2012 ◽  
Vol 8 (S292) ◽  
pp. 190-190
Author(s):  
J. M. Chen ◽  
L. W. Jia ◽  
E. W. Liang
Keyword(s):  
Gamma Ray ◽  
Formation Rate ◽  
Neutral Hydrogen ◽  
Statistical Properties ◽  
Host Galaxy ◽  
Host Galaxies ◽  
Gamma Ray Burst ◽  
Star Forming ◽  
Hydrogen Column Density ◽  
Linear Fit

AbstractGRBs are the most luminous events in the Universe. They are detectable from local to high-z universe and may serve as probes for high-z galaxies (e.g., Savaglio et al. 2009; Kewley & Dopita 2002). We compile the observations for 61 GRB host galaxies from literature. Their redshifts range from 0.0085 to 6.295. We present the statistical properties of the GRB host galaxies, including the stellar mass (M*), star-forming rate (SFR), metallicity (Z), extinction (AV), and neutral hydrogen column density (NH). We explore possible correlations among the properties of gamma-ray burst host galaxies and their cosmic evolution with observations of 61 GRB host galaxies. Our results are shown in Figure 1. A clear Z-M* relation is found in our sample, which is Z ~ M0.4. The host galaxies of local GRBs with detection of accompanied supernovae also share the same relation with high-z GRB host galaxies. A trend that a more massive host galaxy tends to have a higher star-formation rate is found. The best linear fit gives a tentative relation, i.e, SFR ~ M0.75. No any correlation is found between AV and NH. A GRB host galaxy at a higher redshift also tends to have a higher SFR. Even in the same redshift, the SFR may vary over three orders of magnitude. The metallicity of the GRB host galaxies is statistically higher than that of the QSO DLAs. The full version of our results please refer to Chen et al. (2012).

scholarly journals Obscured AGN at 1.5 < z < 3.0 from the zCOSMOS-deep Survey

2019 ◽  
Vol 626 ◽  
pp. A9 ◽  
Author(s):  
M. Mignoli ◽  
A. Feltre ◽  
A. Bongiorno ◽  
F. Calura ◽  
R. Gilli ◽  
...  
Keyword(s):  
Physical Properties ◽  
Emission Line ◽  
Metal Content ◽  
High Redshift ◽  
Strong Relationship ◽  
Emission Lines ◽  
Host Galaxy ◽  
Host Galaxies ◽  
Uv Emission

Context. The physics and demographics of high-redshift obscured active galactic nuclei (AGN) is still scarcely investigated. New samples of such objects, selected with different techniques, can provide useful insights into their physical properties. Aims. With the goal to determine the properties of the gas in the emitting region of type 2 AGN, in particular, the gas metal content, we exploit predictions from photoionization models, including new parameterizations for the distance of gas distribution from the central source and internal microturbulence in the emitting clouds, to interpret rest-frame UV spectral data. Methods. We selected a sample of 90 obscured (type 2) AGN with 1.45 ≤ z ≤ 3.05 from the zCOSMOS-deep galaxy sample by 5σ detection of the high-ionization C IV λ1549 narrow emission line. This feature in a galaxy spectrum is often associated with nuclear activity, and the selection effectiveness has also been confirmed by diagnostic diagrams based on utraviolet (UV) emission-line ratios. We applied the same selection technique and collected a sample of 102 unobscured (type 1) AGN. Taking advantage of the large amount of multiband data available in the COSMOS field, we investigated the properties of the C IV-selected type 2 AGN, focusing on their host galaxies, X-ray emission, and UV emission lines. Finally, we investigated the physical properties of the ionized gas in the narrow-line region (NLR) of this type 2 AGN sample by combining the analysis of strong UV emission lines with predictions from photoionization models. Results. We find that in order to successfully reproduce the relative intensity of UV emission lines of the selected high-z type 2 AGN, two new ingredients in the photoionization models are fundamental: small inner radii of the NLR (≈90 pc for LAGN = 1045 erg s−1), and the internal dissipative microturbulence of the gas-emitting clouds (with vmicr ≈ 100 km s−1). With these modified models, we compute the gas-phase metallicity of the NLR, and our measurements indicate a statistically significant evolution of the metal content with redshift. Finally, we do not observe a strong relationship between the NLR gas metallicity and the stellar mass of the host galaxy in our C IV-selected type 2 AGN sample.

scholarly journals Velocity Offsets Due to Mass Outflows in Active Galaxies

2009 ◽  
Vol 5 (S267) ◽  
pp. 387-392
Author(s):  
D. M. Crenshaw ◽  
S. B. Kraemer ◽  
H. R. Schmitt ◽  
R. F. Mushotzky ◽  
J. P. Dunn
Keyword(s):  
Seyfert Galaxies ◽  
Emission Lines ◽  
Host Galaxy ◽  
Host Galaxies ◽  
Ionized Gas ◽  
Ngc 4151 ◽  
Spatially Resolved ◽  
Mass Outflow ◽  
Ngc 1068 ◽  
Narrow Emission

AbstractWe present a study of the radial velocity offsets between AGN-related narrow emission lines and host-galaxy emission and absorption lines in Seyfert galaxies with observed redshifts less than 0.043. We find that 35% of the Seyferts in the sample show [O iii] emission lines with blueshifts with respect to their host galaxies exceeding 50 km s−1, whereas only 6% show redshifts this large, in qualitative agreement with most previous studies. We also find that a greater percentage of Seyfert 1 galaxies show blueshifts than Seyfert 2 galaxies. Using HST/STIS spatially-resolved spectra of the Seyfert 2 galaxy NGC 1068 and the Seyfert 1 galaxy NGC 4151, we generate geometric models of their narrow-line regions (NLRs) and inner galactic disks and show how these models can explain the blueshifted [O iii] emission lines in collapsed STIS spectra of these two Seyferts. We conclude that the combination of mass outflow of ionized gas in the NLR and extinction by dust in the inner disk (primarily in the form of dust spirals) is primarily responsible for the velocity offsets in Seyfert galaxies.

scholarly journals Host galaxy properties of changing-look AGNs revealed in the MaNGA survey

2020 ◽  
Vol 498 (3) ◽  
pp. 3985-3994
Author(s):  
Xiaoling Yu ◽  
Yong Shi ◽  
Yanmei Chen ◽  
Jianhang Chen ◽  
Songlin Li ◽  
...  
Keyword(s):  
Active Galactic Nuclei ◽  
Main Sequence ◽  
Galactic Nuclei ◽  
Axial Ratio ◽  
Emission Lines ◽  
Host Galaxy ◽  
Type I ◽  
Host Galaxies ◽  
Star Forming ◽  
Nearby Galaxies

ABSTRACT Changing-look active galactic nuclei (CL-AGNs) are a subset of AGNs in which the broad Balmer emission lines appear or disappear within a few years. We use the Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) survey to identify five CL-AGNs. The 2D photometric and kinematic maps reveal common features as well as some unusual properties of CL-AGN hosts as compared to the AGN hosts in general. All MaNGA CL-AGNs reside in the star-forming main sequence, similar to MaNGA non-changing-look AGNs (NCL-AGNs). The $80 \pm 16{{\ \rm per\ cent}}$ of our CL-AGNs do possess pseudo-bulge features, and follow the overall NCL-AGN MBH–σ* relationship. The kinematic measurements indicate that they have similar distributions in the plane of angular momentum versus galaxy ellipticity. MaNGA CL-AGNs, however, show a higher, but not statistically significant ($20 \pm 16{{\ \rm per\ cent}}$) fraction of counter-rotating features compared to that ($1.84 \pm 0.61{{\ \rm per\ cent}}$) in general star formation population. In addition, MaNGA CL-AGNs favour more face-on (axial ratio &gt; 0.7) than that of type I NCL-AGNs. These results suggest that host galaxies could play a role in the CL-AGN phenomenon.

scholarly journals Are strong z ≃ 0.5 MgII absorbers the signature of super-winds?

2006 ◽  
Vol 2 (S235) ◽  
pp. 392-393
Author(s):  
N. Bouché ◽  
M. Murphy ◽  
C. Péroux ◽  
I. Csabai ◽  
V. Wild
Keyword(s):  
Galaxy Formation ◽  
Equivalent Width ◽  
Cross Correlation ◽  
Mass Function ◽  
Physical Models ◽  
Dark Matter Halo ◽  
Host Galaxy ◽  
Host Galaxies ◽  
Cross Correlation Analysis ◽  
The Cross

AbstractBACKGROUND: In the process of galaxy formation, super-nova driven feedback from low-mass galaxies is the process that most readily account for the galaxy mass-metallicity relation and for the shallower galaxy luminosity function (LF) compared to the halo mass function. Absorption-selected galaxies are prime candidates for the sites of starburst activity as (1) they probe the gaseous halos of galaxies up to ~50 kpc (Steidel 1995), and (2) galaxies on the faint end of the LF are likely dominating the statistics. Galaxies selected via their MgII λ2796/2803 doublet absorption against background QSOs are especially well suited as Mg is produced by type II supernova.GOAL: Our project was to constrain the physical models of the gaseous halos by measuring the dark matter halo-mass (Mh) of the MgII host-galaxies statistically, i.e. without identifying spectroscopically the host-galaxy.METHOD: We have used the cross-correlation w(rθ) (over co-moving scales rθ:0.05–13h−1Mpc) between our sample of 1800 z ≃ 0.5 MgII absorbers with equivalent w width W2796r−0.3 Å, and 250,000 Luminous Red Galaxies (LRGs), both selected from SDSS/DR3. The cross-correlation relies on the LRG photometric redshifts, but is not affected from contaminants such as stars or foreground and background galaxies as shown theoretically in Bouché et al. 2005 and empirically in Bouché et al. 2006.RESULTS: From the cross-correlation analysis, we found (Bouché et al. 2006) (i) that the absorber host-halo mean mass is 〈 log Mh (M⊙)〉 = 11.94 ±0.31(stat)+0.24−0.25(sys), i.e. about 1/2 L*, and (ii) an anti-correlation between halo mass Mh and equivalent width W2796r.INTERPRETATION: One SDSS MgII absorber (system) is made of several sub-components or clouds and the stronger the equivalent with of the absorber, the more clouds per system spread over a larger velocity range (Δv). This follows since each sub-component has a velocity width of ~ 5 kms s−1 (Churchill 1997). As result, the equivalent width W2796r is a measure of velocity width (Δv) as demonstrated by Ellison 2006. Together with our SDSS results, these relations imply a mass–velocity Mh–Δv anti-correlation. If the clouds in the host-halos were virialized, velocity and mass would have been correlated.CONCLUSION: Therefore, our Mh–Δv anti-correlation shows that the clouds are not virialized in the gaseous halos of the hosts. This conclusion is best understood in the context of starburst driven outflows where the velocity Δv is related to bulk motion. This opens the possibility to study M82-analogs up to z ~ 2.0 using the MgII selection.

scholarly journals Exploring the pattern of the Galactic HI foreground of GRBs with the ATCA

2019 ◽  
Author(s):  
H Dénes ◽  
P A Jones ◽  
L V Tóth ◽  
S Zahorecz ◽  
B-C Koo ◽  
...  
Keyword(s):  
Column Density ◽  
Gamma Ray ◽  
Neutral Hydrogen ◽  
Far Infrared ◽  
Host Galaxy ◽  
Valuable Insight ◽  
Host Galaxies ◽  
Sky Survey ◽  
Hydrogen Column Density ◽  
Density Values

Abstract The afterglow of a gamma ray burst (GRB) can give us valuable insight into the properties of its host galaxy. To correctly interpret the spectra of the afterglow we need to have a good understanding of the foreground interstellar medium (ISM) in our own Galaxy. The common practice to correct for the foreground is to use neutral hydrogen (H i) data from the Leiden/Argentina/Bonn (LAB) survey. However, the poor spatial resolution of the single dish data may have a significant effect on the derived column densities. To investigate this, we present new high-resolution H i observations with the Australia Telescope Compact Array (ATCA) towards 4 GRBs. We combine the interferometric ATCA data with single dish data from the Galactic All Sky Survey (GASS) and derive new Galactic H i column densities towards the GRBs. We use these new foreground column densities to fit the Swift XRT X-ray spectra and calculate new intrinsic hydrogen column density values for the GRB host galaxies. We find that the new ATCA data shows higher Galactic H i column densities compared to the previous single dish data, which results in lower intrinsic column densities for the hosts. We investigate the line of sight optical depth near the GRBs and find that it may not be negligible towards one of the GRBs, which indicates that the intrinsic hydrogen column density of its host galaxy may be even lower. In addition, we compare our results to column densities derived from far-infrared data and find a reasonable agreement with the H i data.

scholarly journals Testing the evolution of correlations between supermassive black holes and their host galaxies using eight strongly lensed quasars

2020 ◽  
Vol 501 (1) ◽  
pp. 269-280
Author(s):  
Xuheng Ding ◽  
Tommaso Treu ◽  
Simon Birrer ◽  
Adriano Agnello ◽  
Dominique Sluse ◽  
...  
Keyword(s):  
Black Holes ◽  
Hubble Space Telescope ◽  
High Redshift ◽  
Galactic Nuclei ◽  
Host Galaxy ◽  
Wide Field ◽  
Host Galaxies ◽  
Field Surveys ◽  
Instrumental Resolution ◽  
The Moment

ABSTRACT One of the main challenges in using high-redshift active galactic nuclei (AGNs) to study the correlations between the mass of a supermassive black hole ($\mathcal {M}_{\rm BH}$) and the properties of its active host galaxy is instrumental resolution. Strong lensing magnification effectively increases instrumental resolution and thus helps to address this challenge. In this work, we study eight strongly lensed AGNs with deep Hubble Space Telescope imaging, using the lens modelling code lenstronomy to reconstruct the image of the source. Using the reconstructed brightness of the host galaxy, we infer the host galaxy stellar mass based on stellar population models. $\mathcal {M}_{\rm BH}$ are estimated from broad emission lines using standard methods. Our results are in good agreement with recent work based on non-lensed AGNs, demonstrating the potential of using strongly lensed AGNs to extend the study of the correlations to higher redshifts. At the moment, the sample size of lensed AGNs is small and thus they provide mostly a consistency check on systematic errors related to resolution for non-lensed AGNs. However, the number of known lensed AGNs is expected to increase dramatically in the next few years, through dedicated searches in ground- and space-based wide-field surveys, and they may become a key diagnostic of black holes and galaxy co-evolution.

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