scholarly journals FLASH early science – discovery of an intervening H i 21-cm absorber from an ASKAP survey of the GAMA 23 field

2020 ◽  
Vol 494 (3) ◽  
pp. 3627-3641 ◽  
Author(s):  
J R Allison ◽  
E M Sadler ◽  
S Bellstedt ◽  
L J M Davies ◽  
S P Driver ◽  
...  
Keyword(s):  
Path Length ◽  
Column Density ◽  
Radio Sources ◽  
Early Type ◽  
Absorption Path Length ◽  
Spin Temperature ◽  
Upper Limits ◽  
Blind Search ◽  
Cross Matching ◽  
Early Type Galaxy

ABSTRACT We present early science results from the First Large Absorption Survey in H i (FLASH), a spectroscopically blind survey for 21-cm absorption lines in cold hydrogen (H i) gas at cosmological distances using the Australian Square Kilometre Array Pathfinder (ASKAP). We have searched for H i absorption towards 1253 radio sources in the GAMA 23 field, covering redshifts between z = 0.34 and 0.79 over a sky area of approximately 50 deg2. In a purely blind search, we did not obtain any detections of 21-cm absorbers above our reliability threshold. Assuming a fiducial value for the H i spin temperature of Tspin = 100 K and source covering fraction cf = 1, the total comoving absorption path-length sensitive to all Damped Lyman α Absorbers (DLAs; NH i ≥ 2 × 1020 cm−2) is ΔX = 6.6 ± 0.3 (Δz = 3.7 ± 0.2) and super-DLAs (NH i ≥ 2 × 1021 cm−2) is ΔX = 111 ± 6 (Δz= 63 ± 3). We estimate upper limits on the H i column density frequency distribution function that are consistent with measurements from prior surveys for redshifted optical DLAs, and nearby 21-cm emission and absorption. By cross-matching our sample of radio sources with optical spectroscopic identifications of galaxies in the GAMA 23 field, we were able to detect 21-cm absorption at z = 0.3562 towards NVSS J224500−343030, with a column density of $N_{\rm H\,\small{I}} = (1.2 \pm 0.1) \times 10^{20}\, (T_{\rm spin}/100\, \mathrm{K})$ cm−2. The absorber is associated with GAMA J22450.05−343031.7, a massive early-type galaxy at an impact parameter of 17 kpc with respect to the radio source and which may contain a massive (MH i ≳ 3 × 109 M⊙) gas disc. Such gas-rich early types are rare, but have been detected in the nearby Universe.

scholarly journals Constraining magnetic fields in the circumgalactic medium

2020 ◽  
Vol 496 (3) ◽  
pp. 3142-3151 ◽  
Author(s):  
Ting-Wen Lan 藍鼎文 ◽  
J Xavier Prochaska
Keyword(s):  
Magnetic Fields ◽  
Column Density ◽  
High Redshift ◽  
Line Of Sight ◽  
Radio Sources ◽  
Number Density ◽  
Ionized Gas ◽  
Upper Limits ◽  
Circumgalactic Medium ◽  
Magnetohydrodynamic Simulations

ABSTRACT We study the properties of magnetic fields in the circumgalactic medium (CGM) of z < 1 galaxies by correlating Faraday rotation measures (RMs) of ∼1000 high-redshift radio sources with the foreground galaxy number density estimated from the DESI Legacy Imaging Surveys. This method enables us to extract signals of RMs contributed by intervening gas around multiple galaxies. Our results show that there is no detectable correlation between the distribution of RMs and the number of foreground galaxies, contrary to several previous results. Utilizing the non-detection signals, we estimate 3σ upper limits to the RMs from the CGM of $\sim \!20 \rm \ rad\, m^{-2}$ within 50 kpc and $\sim \!10 \rm \ rad \, m^{-2}$ at separations of 100 kpc. By adopting a column density distribution of ionized gas obtained from absorption-line measurements, we further estimate the strengths of coherent magnetic fields parallel to the line of sight of $\lt \rm 2 \ \mu G$ in the CGM. We show that the estimated upper limits of RMs and magnetic field strengths are sufficient to constrain outputs of recent galaxy magnetohydrodynamic simulations. Finally, we discuss possible causes for the inconsistency between our results and previous works.

scholarly journals uGMRT HI 21-cm absorption observations of two extremely inverted spectrum sources

2020 ◽  
Vol 643 ◽  
pp. A174
Author(s):  
Mukul Mhaskey ◽  
Surajit Paul ◽  
Neeraj Gupta ◽  
Dipanjan Mukherjee ◽  
Gopal-Krishna
Keyword(s):  
Optical Depth ◽  
Column Density ◽  
Radio Galaxies ◽  
Radio Spectrum ◽  
Absorption Feature ◽  
Radio Sources ◽  
Spin Temperature ◽  
Inverted Spectrum ◽  
Spectrum Radio ◽  
Thick Part

We report the detection of HI 21-cm absorption in a member of the rare and recently discovered class of compact radio sources: extremely inverted spectrum extragalactic radio sources (EISERS). The EISERS conceivably form a special subclass of the inverted spectrum radio galaxies since the spectral index of the optically thick part of the spectrum for these sources crosses the synchrotron self-absorption limit of α = +2.5 (S(ν) ∝ να). We searched for HI absorption in two EISERS using the recently upgraded Giant Metrewave Radio Telescope (uGMRT) and detected an absorption feature in one of them. The strong associated HI absorption detected against the source J1209−2032 (z = 0.4040) implies an optical depth of 0.178 ± 0.02, corresponding to an HI column density of 34.8 ± 2.9 × 1020 cm−2, for an assumed HI spin temperature of 100 K and covering factor of 1. This is among the highest known optical depth and HI column densities found for compact radio sources of peaked spectrum type and supports the free-free absorption model for the steeply inverted radio spectrum of this source. For the other source, J1549+5038 (z = 2.171), no HI absorption was detected in our observations.

scholarly journals MNELLS: the MUSE nearby early-type galaxy lens locator survey

2020 ◽  
Vol 494 (1) ◽  
pp. 271-292 ◽  
Author(s):  
William P Collier ◽  
Russell J Smith ◽  
John R Lucey
Keyword(s):  
Detection Threshold ◽  
Mass Function ◽  
Initial Mass Function ◽  
Short Exposure ◽  
Early Type ◽  
Upper Limits ◽  
First Results ◽  
Robust Measurements ◽  
Blind Search ◽  
Factor Α

ABSTRACT Low-redshift strong-lensing galaxies can provide robust measurements of the stellar mass-to-light ratios in early-type galaxies (ETGs), and hence constrain variations in the stellar initial mass function (IMF). At present, only a few such systems are known. Here, we report the first results from a blind search for gravitationally lensed emission-line sources behind 52 massive z < 0.07 ETGs with Multi-Unit Spectroscopic Explorer (MUSE) integral field spectroscopy. For 16 galaxies, new observations were acquired, whilst the other 36 were analysed from archival data. This project has previously yielded one confirmed galaxy-scale strong lens (J0403−0239) that we report in an earlier paper. J0403−0239 has since received follow-up observations, presented here, which indicate support for our earlier IMF results. Three cluster-scale, and hence dark-matter-dominated, lensing systems were also discovered (central galaxies of A4059, A2052, and AS555). For nine further galaxies, we detect a singly imaged but closely projected source within 6 arcsec (including one candidate with sources at three different redshifts); such cases can be exploited to derive upper limits on the IMF mass-excess factor, α. Combining the new lens and new upper limits, with the previously discovered systems, we infer an average 〈α〉 = 1.06 ± 0.08 (marginalized over the intrinsic scatter), which is inconsistent with a Salpeter-like IMF (α = 1.55) at the 6σ level. We test the detection threshold in these short-exposure MUSE observations with the injection and recovery of simulated sources, and predict that one in 25 observations is expected to yield a new strong-lens system. Our observational results are consistent with this expected yield.

Stellar Metallicities and Type Ia Supernova Rates in the Early‐Type Galaxy NGC 5846 fromROSATandASCAObservations

1999 ◽  
Vol 514 (2) ◽  
pp. 844-855 ◽  
Author(s):  
A. Finoguenov ◽  
C. Jones ◽  
W. Forman ◽  
L. David
Keyword(s):  
Early Type ◽  
Type Ia Supernova ◽  
Type Ia ◽  
Early Type Galaxy

scholarly journals Survey of Gravitationally Lensed Objects in HSC Imaging (SuGOHI) – VII. Discovery and confirmation of three strongly lensed quasars†

2021 ◽  
Vol 502 (1) ◽  
pp. 1487-1493
Author(s):  
Anton T Jaelani ◽  
Cristian E Rusu ◽  
Issha Kayo ◽  
Anupreeta More ◽  
Alessandro Sonnenfeld ◽  
...  
Keyword(s):  
Spectroscopic Data ◽  
Point Sources ◽  
Sloan Digital Sky Survey ◽  
Early Type ◽  
Blue Point ◽  
X Ray ◽  
Quasar Spectra ◽  
Strategic Program ◽  
Early Type Galaxy

ABSTRACT We present spectroscopic confirmation of three new two-image gravitationally lensed quasars, compiled from existing strong lens and X-ray catalogues. Images of HSC J091843.27–022007.5 show a red galaxy with two blue point sources at either side, separated by 2.26 arcsec. This system has a source and a lens redshifts zs = 0.804 and zℓ = 0.459, respectively, as obtained by our follow-up spectroscopic data. CXCO J100201.50+020330.0 shows two point sources separated by 0.85 arcsec on either side of an early-type galaxy. The follow-up spectroscopic data confirm the fainter quasar has the same redshift with the brighter quasar from the Sloan Digital Sky Survey (SDSS) fiber spectrum at zs = 2.016. The deflecting foreground galaxy is a typical early-type galaxy at a redshift of zℓ = 0.439. SDSS J135944.21+012809.8 has two point sources with quasar spectra at the same redshift zs = 1.096, separated by 1.05 arcsec, and fits to the HSC images confirm the presence of a galaxy between these. These discoveries demonstrate the power of the Hyper Suprime-Cam Subaru Strategic Program (HSC-SSP)’s deep imaging and wide sky coverage. Combined with existing X-ray source catalogues and follow-up spectroscopy, the HSC-SSP provides us unique opportunities to find multiple-image quasars lensed by a foreground galaxy.

Supermassive Black Hole feedback in early type galaxies

2020 ◽  
Vol 15 (S359) ◽  
pp. 119-125
Author(s):  
W. Forman ◽  
C. Jones ◽  
A. Bogdan ◽  
R. Kraft ◽  
E. Churazov ◽  
...  
Keyword(s):  
Dark Matter Halo ◽  
Scaling Relations ◽  
Radio Sources ◽  
Early Type ◽  
X Ray ◽  
Galaxy Groups ◽  
Sufficient Energy ◽  
The Galaxy ◽  
Simple Scaling ◽  
Halo Masses

AbstractOptically luminous early type galaxies host X-ray luminous, hot atmospheres. These hot atmospheres, which we refer to as coronae, undergo the same cooling and feedback processes as are commonly found in their more massive cousins, the gas rich atmospheres of galaxy groups and galaxy clusters. In particular, the hot coronae around galaxies radiatively cool and show cavities in X-ray images that are filled with relativistic plasma originating from jets powered by supermassive black holes (SMBH) at the galaxy centers. We discuss the SMBH feedback using an X-ray survey of early type galaxies carried out using Chandra X-ray Observatory observations. Early type galaxies with coronae very commonly have weak X-ray active nuclei and have associated radio sources. Based on the enthalpy of observed cavities in the coronae, there is sufficient energy to “balance” the observed radiative cooling. There are a very few remarkable examples of optically faint galaxies that are 1) unusually X-ray luminous, 2) have large dark matter halo masses, and 3) have large SMBHs (e.g., NGC4342 and NGC4291). These properties suggest that, in some galaxies, star formation may have been truncated at early times, breaking the simple scaling relations.

scholarly journals Ultradiffuse galaxies in the IC 1459 group from the VEGAS survey

2020 ◽  
Vol 494 (4) ◽  
pp. 5293-5297
Author(s):  
Duncan A Forbes ◽  
Bililign T Dullo ◽  
Jonah Gannon ◽  
Warrick J Couch ◽  
Enrichetta Iodice ◽  
...  
Keyword(s):  
Globular Clusters ◽  
Compact Objects ◽  
Early Type ◽  
Group Members ◽  
Measurement Uncertainties ◽  
Stellar Masses ◽  
Double Nucleus ◽  
Early Type Galaxy

ABSTRACT Using deep g, r, i imaging from the VST Early-type GAlaxy Survey (VEGAS), we have searched for ultradiffuse galaxies (UDGs) in the IC 1459 group. Assuming they are group members, we identify nine galaxies with physical sizes and surface brightnesses that match the UDG criteria within our measurement uncertainties. They have mean colours of g − i = 0.6 and stellar masses of ∼108 M⊙. Several galaxies appear to have associated systems of compact objects, e.g. globular clusters. Two UDGs contain a central bright nucleus, with a third UDG revealing a remarkable double nucleus. This appears to be the first reported detection of a double nucleus in a UDG – its origin is currently unclear.

scholarly journals An early-type galaxy with an inner star-forming disk

2018 ◽  
Author(s):  
Song-lin Li ◽  
Yong Shi ◽  
Yan-Mei Chen ◽  
Matha Tabor ◽  
Dmitry Bizyaev ◽  
...  
Keyword(s):  
Early Type ◽  
Star Forming ◽  
Early Type Galaxy

scholarly journals Upper limits on the mass of supermassive black holes from STIS archival data

2007 ◽  
Vol 3 (S245) ◽  
pp. 233-234
Author(s):  
A. Beifiori ◽  
E. M. Corsini ◽  
E. Dalla Bontà ◽  
A. Pizzella ◽  
L. Coccato ◽  
...  
Keyword(s):  
Black Holes ◽  
Emission Line ◽  
Supermassive Black Holes ◽  
Archival Data ◽  
Early Type ◽  
Preliminary Results ◽  
Upper Limits ◽  
Nearby Galaxies ◽  
Line Widths

AbstractThe growth of supermassive black holes (SMBHs) appears to be closely linked with the formation of spheroids. There is a pressing need to acquire better statistics on SMBH masses, since the existing samples are preferentially weighted toward early-type galaxies with very massive SMBHs. With this motivation we started a project aimed at measuring upper limits on the mass of the SMBHs that can be present in the center of all the nearby galaxies (D < 100 Mpc) for which STIS/G750M spectra are available in the HST archive. These upper limits will be derived by modeling the central emission-line widths ([N II] λλ6548, 6583, Hα and [S II] λλ6716, 6731) observed over an aperture of ~01 (R < 50 pc). Here we present our preliminary results for a subsample of 76 bulges.

On-chip cavity-enhanced absorption spectroscopy using a white light-emitting diode and polymer mirrors

Lab on a Chip ◽  
2015 ◽  
Vol 15 (3) ◽  
pp. 711-717 ◽  
Author(s):  
Cathy M. Rushworth ◽  
Gareth Jones ◽  
Martin Fischlechner ◽  
Emma Walton ◽  
Hywel Morgan
Keyword(s):  
Absorption Spectroscopy ◽  
White Light ◽  
Microfluidic Chip ◽  
Path Length ◽  
Light Emitting Diode ◽  
Absorption Path Length ◽  
Light Emitting ◽  
Enhanced Absorption ◽  
Cavity Enhanced Absorption Spectroscopy ◽  
On Chip

We have integrated disposable polymer mirrors within a microfluidic chip to form a multi-pass cell, which increases the absorption path length by a maximum of 28 times, providing micromolar detection limits in a probed volume of 10 nL.

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