scholarly journals Lyman-α emission from a WISE-selected optically faint powerful radio galaxy M151304.72-252439.7 at z = 3.132*

2020 ◽  
Author(s):  
Gitika Shukla ◽  
Raghunathan Srianand ◽  
Neeraj Gupta ◽  
Patrick Petitjean ◽  
Andrew J Baker ◽  
...  
Keyword(s):  
Velocity Dispersion ◽  
Radio Galaxy ◽  
Narrow Band Imaging ◽  
Wide Field ◽  
Low Velocity ◽  
Compact Component ◽  
Integral Field Spectroscopy ◽  
Spatially Extended ◽  
Infrared Survey ◽  
Powerful Radio Galaxy

Abstract We report the detection of a large (∼90 kpc) and luminous Lyα nebula [LLyα = (6.80±0.08) × 1044  $\rm {\, erg\, s^{-1}}$] around an optically faint (r>23 mag) radio galaxy M1513-2524 at zem=3.132. The double-lobed radio emission has an extent of 184 kpc, but the radio core, i.e., emission associated with the active galactic nucleus (AGN) itself, is barely detected. This object was found as part of our survey to identify high-z quasars based on Wide-field Infrared Survey Explorer (WISE) colors. The optical spectrum has revealed Lyα, N v, C iv and He ii emission lines with a very weak continuum. Based on long-slit spectroscopy and narrow band imaging centered on the Lyα emission, we identify two spatial components: a “compact component” with high velocity dispersion (∼1500 km s−1) seen in all three lines, and an “extended component”, having low velocity dispersion (i.e., 700-1000 km s−1). The emission line ratios are consistent with the compact component being in photoionization equilibrium with an AGN. We also detect spatially extended associated Lyα absorption, which is blue-shifted within 250-400 km s−1 of the Lyα peak. The probability of Lyα absorption detection in such large radio sources is found to be low (∼10%) in the literature. M1513-2524 belongs to the top few percent of the population in terms of Lyα and radio luminosities. Deep integral field spectroscopy is essential for probing this interesting source and its surroundings in more detail.

Ionized gas outflows in the interacting radio galaxy 4C +29.30

2019 ◽  
Vol 15 (S359) ◽  
pp. 262-264
Author(s):  
Guilherme S. Couto ◽  
Thaisa Storchi-Bergmann ◽  
Aneta Siemiginowska ◽  
Rogemar A. Riffel
Keyword(s):  
Velocity Dispersion ◽  
Radio Galaxy ◽  
Host Galaxy ◽  
Ionized Gas ◽  
Bolometric Luminosity ◽  
Integral Field Spectroscopy ◽  
Outflow Rate ◽  
Mass Outflow ◽  
Ambient Gas ◽  
Integral Field

AbstractWe investigate the ionized gas excitation and kinematics in the inner 4.3 × 6.2 kpc2 of the merger radio galaxy 4C +29.30. Using optical integral field spectroscopy with the Gemini North Telescope, we find signatures of gas outflows, including high blueshifts of up to ∼−650 km s−1 observed in a region ∼1″ south of the nucleus, which also presents high velocity dispersion (∼250 km s−1). A possible redshifted counterpart is observed north from the nucleus. We propose that these regions correspond to a bipolar outflow possibly due to the interaction of the radio jet with the ambient gas. We estimate a total ionized gas mass outflow rate of $\[{\dot M_{out}} = 18.1\begin{array}{c} + 8.2\\ - 5.3\end{array}{\kern 1pt} {\kern 1pt} \]$ with a kinetic power of $\[\dot E = 5.8\begin{array}{c} + 7.6\\ - 2.9\end{array} \times {10^{42}}{\kern 1pt} {\kern 1pt} \]$ , which represents $\[3.9\begin{array}{c} + 5.1\\ - 1.5\end{array}\% \]$ of the AGN bolometric luminosity. These values are higher than usually observed in nearby active galaxies and could imply a significant impact of the outflows on the evolution of the host galaxy.

Motions of neutral hydrogen at high latitudes

1967 ◽  
Vol 31 ◽  
pp. 265-278 ◽  
Author(s):  
A. Blaauw ◽  
I. Fejes ◽  
C. R. Tolbert ◽  
A. N. M. Hulsbosch ◽  
E. Raimond
Keyword(s):  
Surface Density ◽  
Velocity Dispersion ◽  
Neutral Hydrogen ◽  
Hydrogen Gas ◽  
High Latitudes ◽  
Low Velocity

Earlier investigations have shown that there is a preponderance of negative velocities in the hydrogen gas at high latitudes, and that in certain areas very little low-velocity gas occurs. In the region 100° <l< 250°, + 40° <b< + 85°, there appears to be a disturbance, with velocities between - 30 and - 80 km/sec. This ‘streaming’ involves about 3000 (r/100)2solar masses (rin pc). In the same region there is a low surface density at low velocities (|V| < 30 km/sec). About 40% of the gas in the disturbance is in the form of separate concentrations superimposed on a relatively smooth background. The number of these concentrations as a function of velocity remains constant from - 30 to - 60 km/sec but drops rapidly at higher negative velocities. The velocity dispersion in the concentrations varies little about 6·2 km/sec. Concentrations at positive velocities are much less abundant.

scholarly journals Extinction-free Census of AGNs in the AKARI/IRC North Ecliptic Pole Field from 23-band infrared photometry from Space Telescopes

2020 ◽  
Vol 499 (3) ◽  
pp. 4068-4081 ◽  
Author(s):  
Ting-Wen Wang ◽  
Tomotsugu Goto ◽  
Seong Jin Kim ◽  
Tetsuya Hashimoto ◽  
Denis Burgarella ◽  
...  
Keyword(s):  
Spectral Energy Distribution ◽  
Cosmic Time ◽  
Spectral Energy ◽  
Wide Field ◽  
Space Telescopes ◽  
Distribution Modelling ◽  
Star Forming ◽  
The North ◽  
Band Filter ◽  
Infrared Survey

ABSTRACT In order to understand the interaction between the central black hole and the whole galaxy or their co-evolution history along with cosmic time, a complete census of active galactic nucleus (AGN) is crucial. However, AGNs are often missed in optical, UV, and soft X-ray observations since they could be obscured by gas and dust. A mid-infrared (MIR) survey supported by multiwavelength data is one of the best ways to find obscured AGN activities because it suffers less from extinction. Previous large IR photometric surveys, e.g. Wide field Infrared Survey Explorer and Spitzer, have gaps between the MIR filters. Therefore, star-forming galaxy-AGN diagnostics in the MIR were limited. The AKARI satellite has a unique continuous nine-band filter coverage in the near to MIR wavelengths. In this work, we take advantage of the state-of-the-art spectral energy distribution modelling software, cigale, to find AGNs in MIR. We found 126 AGNs in the North Ecliptic Pole-Wide field with this method. We also investigate the energy released from the AGN as a fraction of the total IR luminosity of a galaxy. We found that the AGN contribution is larger at higher redshifts for a given IR luminosity. With the upcoming deep IR surveys, e.g. JWST, we expect to find more AGNs with our method.

scholarly journals The stellar structure of early-type galaxies: a wide-field Mitchell Spectrograph view

2016 ◽  
Vol 11 (S321) ◽  
pp. 288-288
Author(s):  
N. F. Boardman ◽  
A. Weijmans ◽  
R. C. E. van den Bosch ◽  
L. Zhu ◽  
A. Yildirim ◽  
...  
Keyword(s):  
Effective Radius ◽  
Stellar Structure ◽  
Wide Field ◽  
Early Type ◽  
Integral Field Spectroscopy ◽  
Field Spectroscopy ◽  
Integral Field ◽  
Made In

Much progress has been made in recent years towards understanding how early-type galaxies (ETGs) form and evolve. SAURON (Bacon et al. 2001) integral-field spectroscopy from the ATLAS3D survey (Cappellari et al. 2011) has suggested that less massive ETGs are linked directly to spirals, whereas the most massive objects appear to form from a series of merging and accretion events (Cappellari et al. 2013). However, the ATLAS3D data typically only extends to about one half-light radius (or effective radius, Re), making it unclear if this picture is truly complete.

scholarly journals Resolved Gas Kinematics in a Sample of Low-Redshift High Star-Formation Rate Galaxies

2016 ◽  
Vol 33 ◽  
Author(s):  
Mathew Varidel ◽  
Michael Pracy ◽  
Scott Croom ◽  
Matt S. Owers ◽  
Elaine Sadler
Keyword(s):  
Star Formation ◽  
Velocity Gradient ◽  
Velocity Dispersion ◽  
Star Formation Rate ◽  
Formation Rate ◽  
Local Effect ◽  
Line Of Sight ◽  
Mean Velocity ◽  
Gas Kinematics ◽  
Integral Field Spectroscopy

AbstractWe have used integral field spectroscopy of a sample of six nearby (z ~ 0.01–0.04) high star-formation rate ($\text{SFR} \sim 10\hbox{--}40$$\text{M}_\odot \text{ yr$^{-1}$}$) galaxies to investigate the relationship between local velocity dispersion and star-formation rate on sub-galactic scales. The low-redshift mitigates, to some extent, the effect of beam smearing which artificially inflates the measured dispersion as it combines regions with different line-of-sight velocities into a single spatial pixel. We compare the parametric maps of the velocity dispersion with the Hα flux (a proxy for local star-formation rate), and the velocity gradient (a proxy for the local effect of beam smearing). We find, even for these very nearby galaxies, the Hα velocity dispersion correlates more strongly with velocity gradient than with Hα flux—implying that beam smearing is still having a significant effect on the velocity dispersion measurements. We obtain a first-order non parametric correction for the unweighted and flux weighted mean velocity dispersion by fitting a 2D linear regression model to the spaxel-by-spaxel data where the velocity gradient and the Hα flux are the independent variables and the velocity dispersion is the dependent variable; and then extrapolating to zero velocity gradient. The corrected velocity dispersions are a factor of ~ 1.3–4.5 and ~ 1.3–2.7 lower than the uncorrected flux-weighted and unweighted mean line-of-sight velocity dispersion values, respectively. These corrections are larger than has been previously cited using disc models of the velocity and velocity dispersion field to correct for beam smearing. The corrected flux-weighted velocity dispersion values are σm ~ 20–50 km s−1.

Detection and correlation of geosynchronous objects in NASA’s Wide-field Infrared Survey Explorer images

2021 ◽  
Author(s):  
Joshua Fitzmaurice ◽  
Donald Bédard ◽  
Chris H. Lee ◽  
Patrick Seitzer
Keyword(s):  
Wide Field ◽  
Infrared Survey

scholarly journals The nature and likely redshift of GLEAM J0917–0012

2021 ◽  
Vol 38 ◽  
Author(s):  
Guillaume Drouart ◽  
Nick Seymour ◽  
Jess W. Broderick ◽  
José Afonso ◽  
Rajan Chhetri ◽  
...  
Keyword(s):  
Radio Galaxy ◽  
Emission Lines ◽  
Optical Data ◽  
Space Observatory ◽  
Very Large Array ◽  
Murchison Widefield Array ◽  
Original Interpretation ◽  
Independent Confirmation ◽  
Infrared Survey

Abstract We previously reported a putative detection of a radio galaxy at $z=10.15$ , selected from the GaLactic and Extragalactic All-sky Murchison Widefield Array (GLEAM) survey. The redshift of this source, GLEAM J0917–0012, was based on three weakly detected molecular emission lines observed with the Atacama Large Millimetre Array (ALMA). In order to confirm this result, we conducted deep spectroscopic follow-up observations with ALMA and the Karl Jansky Very Large Array (VLA). The ALMA observations targeted the same CO lines previously reported in Band 3 (84–115 GHz) and the VLA targeted the CO(4-3) and [CI(1-0)] lines for an independent confirmation in Q-band (41 and 44 GHz). Neither observation detected any emission lines, removing support for our original interpretation. Adding publicly available optical data from the Hyper Suprime-Cam survey, Widefield Infrared Survey Explorer (WISE), and Herschel Space Observatory in the infrared, as well as $<$ 10 GHz polarisation and 162 MHz inter-planetary scintillation observations, we model the physical and observational characteristics of GLEAM J0917–0012 as a function of redshift. Comparing these predictions and observational relations to the data, we are able to constrain its nature and distance. We argue that if GLEAM J0917–0012 is at $z<3,$ then it has an extremely unusual nature, and that the more likely solution is that the source lies above $z=7$ .

scholarly journals Challenges in Timeseries Analysis from Microlensing

2016 ◽  
Vol 12 (S325) ◽  
pp. 253-258
Author(s):  
R. A. Street
Keyword(s):  
Data Analysis ◽  
Software Development ◽  
Formation Mechanisms ◽  
Wide Field ◽  
Detection Techniques ◽  
Timeseries Analysis ◽  
Modeling Software ◽  
New Software Development ◽  
Host Stars ◽  
Infrared Survey

AbstractDespite a flood of discoveries over the last ~ 20 years, our knowledge of the exoplanet population is incomplete owing to a gap between the sensitivities of different detection techniques. However, a census of exoplanets at all separations from their host stars is essential to fully understand planet formation mechanisms. Microlensing offers an effective way to bridge the gap around 1–10 AU and is therefore one of the major science goals of the Wide Field Infrared Survey Telescope (WFIRST) mission. WFIRST’s survey of the Galactic Bulge is expected to discover ~ 20,000 microlensing events, including ~ 3000 planets, which represents a substantial data analysis challenge with the modeling software currently available. This paper highlights areas where further work is needed. The community is encouraged to join new software development efforts aimed at making the modeling of microlensing events both more accessible and rigorous.

Sign in / Sign up

Export Citation Format

Share Document