Observations of the Sunyaev–Zel'dovich effect at high angular resolution towards the galaxy clusters A665, A2163 and CL0016+16

Studies of molecular clouds in nearby galaxies require high angular resolution. Ten arcseconds corresponds to 0.5 kpc at the distance of M51. Typical gigant molecular clouds (GMC:s) have a size of 5-30 pc (Solomon et al. 1985). However complexes of GMC: s (Superclouds) can be several hundred parsecs (Elmegreen 1985; Rivolo et al. 1985). The higest angular resolution achived in CO(J=1-0) line observations of external galaxies is 7” (Lo et al 1984,1985). The resolution problem can be eased by observing M31 with a distance of only ⋍ 690 kpc (10” corresponds to 34 pc), which has been done by Combes et al. 1977a,b; Boulanger et al. 1984; Ryden and Stark 1985; Stark 1985; Blitz 1985; Ichikawa et al. 1985. In M31 the CO emission is strongly concetrated to the spiral arms with a arm interarm ratio of ≥ 25 (Ryden and Stark 1985; Stark 1985). The emission is caused by many small clouds unresolved with present resolution together with some larger clouds. Streaming is observed to occur across the arms. Extragalatic studies have the advantage of being more easy to interpret in terms of arm interarm contrast, noncircular motion, and galatic structure. They also make possible studies of the mass fraction of gas as a function of radius in different morphological types of galxies. Answers to questions like “Do any relation exist between galaxy type and molecular abundance?” are very important for our understanding of galatic evolution.

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MEASUREMENTS OF THE SUNYAEV–ZEL’DOVICH EFFECT IN MACS J0647.7+7015 AND MACS J1206.2–0847 AT HIGH ANGULAR RESOLUTION WITH MUSTANG

The Astrophysical Journal ◽

10.1088/0004-637x/809/2/185 ◽

2015 ◽

Vol 809 (2) ◽

pp. 185 ◽

Cited By ~ 11

Author(s):

Alexander H. Young ◽

Tony Mroczkowski ◽

Charles Romero ◽

Jack Sayers ◽

Italo Balestra ◽

...

Keyword(s):

Angular Resolution ◽

High Angular Resolution ◽

Sunyaev Zel'dovich Effect

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Galactic Plane Surveys at Low Frequencies

Symposium - International Astronomical Union ◽

10.1017/s0074180900169050 ◽

2002 ◽

Vol 199 ◽

pp. 251-258

Author(s):

A.R. Taylor

Keyword(s):

Interstellar Medium ◽

Atomic Hydrogen ◽

Angular Resolution ◽

Spatial Scales ◽

High Sensitivity ◽

Hydrogen Gas ◽

Dimensional Structure ◽

High Angular Resolution ◽

Wide Field ◽

The Galaxy

Until recently, high angular resolution and high sensitivity surveys of the radio emission from the plane of our Galaxy were available only at frequencies of several GHz, where large single dish radio telescopes provide arcminute scale angular resolution. At these frequencies thermal radiation from HII regions and diffuse ionized gas comprise a major component of the Galactic emission. Advances in wide field interferometric imaging techniques now make it possible to carry out high sensitivity surveys of the Galaxy with arcminute scale angular resolution at 1.4 GHz and below. Over the past few years initial synthesis surveys have been made. More ambitious surveys that combined sensitive continuum observations with full polarimetry and images of the 3-dimensional structure of atomic hydrogen gas at pc scales are currently underway in the northern (DRAO) and southern (ATNF) hemispheres. The interstellar medium of the Galaxy contains structure on all spatial scales, and these surveys combined data from aperture synthesis telescopes and signal dish antennas to provide full spatial frequency coverage to the resolution limit. Preliminary results reveal wide-spread features and processes in the the interstellar medium that are not readily visible by other means, including, for example, unusual atomic hydrogen structures related to the vertical transfer of matter and radiation between the disk and halo of the Galaxy, Faraday rotation structures that allow study of the magnetic field and diffuse ionized component in the plane of the Galaxy, and a cold atomic phase of the neutral medium that may provide a link between global shock phenomena in the galaxy and the formation of molecular clouds.

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Search for and Identification of Young Compact Galactic Supernova Remnants Using THOR

Universe ◽

10.3390/universe7090338 ◽

2021 ◽

Vol 7 (9) ◽

pp. 338

Author(s):

Sujith Ranasinghe ◽

Denis Leahy ◽

Jeroen Stil

Keyword(s):

Absorption Spectra ◽

Supernova Remnants ◽

Angular Resolution ◽

High Angular Resolution ◽

Observational Constraints ◽

Selection Effects ◽

Survey Area ◽

Sensitivity Limit ◽

Expected Number ◽

The Galaxy

Young Supernova remnants (SNRs) with smaller angular sizes are likely missing from existing radio SNR catalogues, caused by observational constraints and selection effects. In order to find new compact radio SNR candidates, we searched the high angular resolution (25″) THOR radio survey of the first quadrant of the galaxy. We selected sources with non-thermal radio spectra. HI absorption spectra and channel maps were used to identify which sources are galactic and to estimate their distances. Two new compact SNRs were found: G31.299-0.493 and G18.760-0.072, of which the latter was a previously suggested SNR candidate. The distances to these SNRs are 5.0±0.3 kpc and 4.7±0.2 kpc, respectively. Based on the SN rate in the galaxy or on the statistics of known SNRs, we estimate that there are 15–20 not-yet detected compact SNRs in the galaxy and that the THOR survey area should contain three or four. Our detection of two SNRs (half the expected number) is consistent with the THOR sensitivity limit compared with the distribution of integrated flux densities of SNRs.

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GALACTICNUCLEUS: A high angular-resolution JHKs imaging survey of the Galactic centre

Astronomy and Astrophysics ◽

10.1051/0004-6361/202038606 ◽

2020 ◽

Vol 641 ◽

pp. A141

Author(s):

F. Nogueras-Lara ◽

R. Schödel ◽

N. Neumayer ◽

E. Gallego-Cano ◽

B. Shahzamanian ◽

...

Keyword(s):

Stellar Population ◽

Near Infrared ◽

Angular Resolution ◽

Interstellar Extinction ◽

Extinction Curve ◽

Line Of Sight ◽

Galactic Centre ◽

High Angular Resolution ◽

The Galaxy ◽

Red Clump

Context. The characterisation of the extinction curve in the near-infrared (NIR) is fundamental to analysing the structure and stellar population of the Galactic centre (GC), whose analysis is hampered by the extreme interstellar extinction (AV ~ 30 mag) that varies on arc-second scales. Recent studies indicate that the behaviour of the extinction curve might be more complex than previously assumed, pointing towards a variation of the extinction curve as a function of wavelength. Aims. We aim to analyse the variations of the extinction index, α, with wavelength, line-of-sight, and absolute extinction, extending previous analyses to a larger area of the innermost regions of the Galaxy. Methods. We analysed the whole GALACTICNUCLEUS survey, a high-angular resolution (~0.2″) JHKs NIR survey specially designed to observe the GC in unprecedented detail. It covers a region of ~6000 pc2, comprising fields in the nuclear stellar disc, the inner bulge, and the transition region between them. We applied two independent methods based on red clump (RC) stars to constrain the extinction curve and analysed its variation superseding previous studies. Results. We used more than 165 000 RC stars and increased the size of the regions analysed significantly to confirm that the extinction curve varies with the wavelength. We estimated a difference Δα = 0.21 ± 0.07 between the obtained extinction indices, αJH = 2.44 ± 0.05 and αHKs = 2.23 ± 0.05. We also concluded that there is no significant variation of the extinction curve with wavelength, with the line-of-sight or the absolute extinction. Finally, we computed the ratios between extinctions, AJ∕AH = 1.87 ± 0.03 and AH/AKs = 1.84 ± 0.03, consistent with all the regions of the GALACTICNUCLEUS catalogue.

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Active gas features in three HSC-SSP CAMIRA clusters revealed by high angular resolution analysis of MUSTANG-2 SZE and XXL X-ray observations

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa2330 ◽

2020 ◽

Vol 501 (2) ◽

pp. 1701-1732

Author(s):

Nobuhiro Okabe ◽

Simon Dicker ◽

Dominique Eckert ◽

Tony Mroczkowski ◽

Fabio Gastaldello ◽

...

Keyword(s):

Large Scale ◽

Angular Resolution ◽

Major Axis ◽

High Angular Resolution ◽

X Ray ◽

Spatially Resolved ◽

Sunyaev Zel'dovich Effect ◽

Major Merger ◽

Resolution Analysis ◽

A Minor

ABSTRACT We present results from simultaneous modelling of high angular resolution GBT/MUSTANG-2 90 GHz Sunyaev–Zel’dovich effect (SZE) measurements and XMM-XXL X-ray images of three rich galaxy clusters selected from the HSC-SSP Survey. The combination of high angular resolution SZE and X-ray imaging enables a spatially resolved multicomponent analysis, which is crucial to understand complex distributions of cluster gas properties. The targeted clusters have similar optical richnesses and redshifts, but exhibit different dynamical states in their member galaxy distributions: a single-peaked cluster, a double-peaked cluster, and a cluster belonging to a supercluster. A large-scale residual pattern in both regular Compton-parameter y and X-ray surface brightness distributions is found in the single-peaked cluster, indicating a sloshing mode. The double-peaked cluster shows an X-ray remnant cool core between two SZE peaks associated with galaxy concentrations. The temperatures of the two peaks reach ∼20–30 keV in contrast to the cool core component of ∼2 keV, indicating a violent merger. The main SZE signal for the supercluster is elongated along a direction perpendicular to the major axis of the X-ray core, suggesting a minor merger before core passage. The SX and y distributions are thus perturbed at some level, regardless of the optical properties. We find that the integrated Compton y parameter and the temperature for the major merger are boosted from those expected by the weak-lensing mass and those for the other two clusters show no significant deviations, which is consistent with predictions of numerical simulations.

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THE GALACTIC CENTER

Symposium - International Astronomical Union ◽

10.1017/s0074180900075276 ◽

1981 ◽

Vol 96 ◽

pp. 281-295

Author(s):

Ian Gatley ◽

E. E. Becklin

Keyword(s):

Angular Resolution ◽

Galactic Center ◽

Mass Density ◽

High Angular Resolution ◽

Density Structure ◽

Unique Region ◽

Ultimate Source ◽

The Galaxy ◽

Sgr A ◽

Central Parsec

Recent infrared and radio observations of the Galactic Center are reviewed. For the region between 1 and 100 pc most of the observed phenomena can be explained by a large density of late-type stars, a ring of molecular material, and a number of regions of active star formation. The central parsec (Sgr A) appears to be a unique region of activity in the Galaxy; this result is based on recent high angular resolution data at 30 to 100 μm and high resolution spectral line observations at 12.8 μm. The observations are discussed in terms of the mass, density structure, and luminosity of the region; the ultimate source of the activity is discussed.

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Sunyaev-Zel'dovich effect and the dust emission in the galaxy clusters

Advances in Space Research ◽

10.1016/0273-1177(84)90127-3 ◽

1984 ◽

Vol 3 (10-12) ◽

pp. 443-446 ◽

Cited By ~ 1

Author(s):

N.V. Voshchinnikov ◽

V.K. Khersonskij

Keyword(s):

Galaxy Clusters ◽

Dust Emission ◽

The Galaxy ◽

Sunyaev Zel'dovich Effect

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