scholarly journals New HI Observations of the prototype Polar Ring Galaxy NGC 4650A

1997 ◽  
Vol 14 (1) ◽  
pp. 92-95
Author(s):  
Magda Arnaboldi
Keyword(s):  
High Resolution ◽  
Velocity Field ◽  
Central Region ◽  
Near Infrared ◽  
New Technology ◽  
Host Galaxy ◽  
Polar Structure ◽  
Polar Ring ◽  
Compact Array ◽  
Band Image

AbstractNew, high-resolution observations of the HI emission line and 20 cm continuum at the Australia Telescope Compact Array (ATCA) for the prototype polar ring galaxy NGC 4650A are presented. They show the presence of a far more extended HI distribution than previously observed with the VLA, and a very regular velocity field out to a distance of ∼50 kpc. The combined analysis of the HI data with optical and near-infrared (NIR) images argues against previous warp models used to describe the dynamics of this object. Further analysis of the new B-band image obtained at the European Southern Observatories New Technology Telescope (NTT) indicates clearly that the polar structure extends continuously to within about 200 pc of the nucleus of the central host galaxy, ruling out the presence of a ‘hole’ in the central region of this component. The presence of two spiral arms stretching out in the polar disk seems to represent the most likely explanation for the observed morphology and kinematics.

Highly Sensitive, Non-cryogenic NIR High-resolution Spectrograph, WINERED

2022 ◽  
Vol 134 (1031) ◽  
pp. 015004
Author(s):  
Yuji Ikeda ◽  
Sohei Kondo ◽  
Shogo Otsubo ◽  
Satoshi Hamano ◽  
Chikako Yasui ◽  
...  
Keyword(s):  
High Resolution ◽  
Near Infrared ◽  
New Technology ◽  
Optical Design ◽  
Wide Band ◽  
Integration Time ◽  
Optical Wavelength ◽  
Custom Made ◽  
Intermediate Size ◽  
Large Telescopes

Abstract WINERED is a novel near-infrared (NIR) high-resolution spectrograph (HRS) that pursues the highest possible sensitivity to realize high-precision spectroscopy in the NIR as in the optical wavelength range. WINERED covers 0.9–1.35 μm (z, Y, and J-bands) with three modes (Wide mode and two Hires modes) at the maximum spectral resolutions of R = 28,000 and R = 70,000. For fulfilling the objective, WINERED is designed with an unprecedentedly high instrument throughput (up to 50% at maximum including the quantum efficiency of the array) that is three times or more than other existing optical/NIR HRSs. This is mainly realized by a combination of non-white pupil and no fiber-fed configuration in optical design, the moderate (optimized) wavelength coverage, and the high-throughput gratings. Another prominent feature of WINERED is “warm” instrument despite for infrared (IR) observations. Such non-cryogenic (no cold stop) IR instrument finally became possible with the combination of custom-made thermal-cut filter of 10−8 class, 1.7 μm cutoff HAWAII-2RG array, and a cold baffle reducing the direct thermal radiation to the IR array into the solid angle of f/2. The thermal background is suppressed below 0.1 photons pixel−1 s−1 even in the wide band of 0.9–1.35 μm under the environment of 290 K. WINERED had been installed to the 3.58 m New Technology Telescope at La Silla Observatory, ESO, since 2017. Even with the intermediate size telescope, WINERED was confirmed to provide a limiting magnitude (for SNR = 30 with 8 hr. integration time) of J = 16.4 mag for the Wide mode and J = 15.1 mag for the Hires mode, respectively, under the natural seeing conditions. These sensitivities are comparable to those for the existing NIR-HRSs attached to the 8–10 m class telescopes with AO. WINERED type spectrographs may become a critical not only for the currently on-going extremely large telescopes to reduce the developing cost and time but also for smaller telescopes to extend their lives with long programs.

scholarly journals Compact Array Mapping of the Nuclear Starburst in NGC 7552

1994 ◽  
Vol 158 ◽  
pp. 355-357
Author(s):  
Duncan A. Forbes ◽  
Ray P. Norris ◽  
Gerry M. Williger ◽  
R. Chris Smith
Keyword(s):  
High Resolution ◽  
Near Infrared ◽  
Starburst Galaxy ◽  
Angular Momenta ◽  
Lindblad Resonance ◽  
Inner Lindblad Resonance ◽  
Compact Array

We discuss new observations of the starburst galaxy NGC 7552. From optical and near–infrared colour maps we find a red, dusty circumnuclear ring. High-resolution radio mapping from the ATCA reveals the same ring, and a number of bright blobs (probably SNRs). The ring is probably associated with gas and dust which have lost angular momenta due to torques in the bar potential and settled at the inner Lindblad resonance. These circumnuclear starburst rings may be relatively common (when mapped without the obscuring affects of dust) and may play a role in collimating material of a nuclear outflow.

scholarly journals Globular clusters in the near–infrared

2009 ◽  
Vol 5 (H15) ◽  
pp. 555-556
Author(s):  
E. Valenti ◽  
L. Origlia ◽  
R. M. Rich
Keyword(s):  
High Resolution ◽  
Ir Spectroscopy ◽  
Galaxy Formation ◽  
Globular Clusters ◽  
Near Infrared ◽  
Stellar Structure ◽  
High Resolution Spectroscopy ◽  
Structure Evolution ◽  
Host Galaxy ◽  
Chemical Enrichment

The study of Globular Cluster (GC) stellar populations (SPs) addresses fundamental astrophysical questions ranging from stellar structure, evolution and dynamics, to Galaxy formation. Indeed, they represent: i) fossils from the remote and violent epoch of Galaxy formation, ii) test particles for studying Galaxy dynamics and stellar dynamical model, and iii) fiducial templates for studying integrated light from distant stellar systems. In particular, high resolution spectroscopy of GC SPs provides abundance patterns which are crucial for understanding the formation and chemical enrichment time–scale of the host galaxy. Here the major results on Galactic GCs based on high-resolution near-infrared (near–IR) spectroscopy are briefly reviewed. Optical and IR spectroscopy are complementary tools to investigate SPs in different environments, the latter being more suitable in the case of moderately–high extinction regions (AV≥2) and high metallicity.

scholarly journals Jet-CO alignments in the environments high-z radio galaxies

2016 ◽  
Vol 11 (S321) ◽  
pp. 348-350
Author(s):  
Bjorn Emonts
Keyword(s):  
Near Infrared ◽  
High Redshift ◽  
Radio Galaxies ◽  
Host Galaxy ◽  
Molecular Gas ◽  
Gas Reservoirs ◽  
Radio Jets ◽  
Low Surface Brightness ◽  
Halo Gas ◽  
Compact Array

AbstractIn the outskirts of massive high-redshift radio galaxies, powerful radio-jets often interact with ambient warm Lyα-emitting gas. We present the discovery of luminous reservoirs of cold molecular gas in these environments, based on CO(1-0) observations with the Australia Telescope Compact Array. The CO-emission is aligned with the radio jets, and found tens of kpc outside the host galaxy. These molecular gas reservoirs have CO luminosities in the range of those found in submm-galaxies (L'CO ~ 4-9 × 1010 K km/s pc2), but they lack any near-infrared counterpart in deep Spitzer imaging. These results suggest that jet-triggered feedback takes place in the circum-galactic environment of high-z radio galaxies. We prefer the interpretation that the CO-emitting gas is formed when the propagating jets enrich, shock and cool pre-existing dusty halo gas. We further argue that sensitive low-surface-brightness CO observations, using radio interferometers in very compact array-configurations, are essential to study the role of the cold molecular medium in the outskirts of massive high-z galaxies.

scholarly journals Polar Ring Galaxies and the Tully-Fisher relation: implications for the dark halo shape

2004 ◽  
Vol 220 ◽  
pp. 405-410
Author(s):  
Magda Arnaboldi ◽  
Enrica Iodice ◽  
Frederick Bournaud ◽  
Francoise Combes ◽  
Linda S. Sparke ◽  
...  
Keyword(s):  
Near Infrared ◽  
Host Galaxy ◽  
Dark Halo ◽  
Line Flux ◽  
Polar Plane ◽  
Polar Ring ◽  
Ring Galaxies ◽  
Fisher Relation ◽  
Larger Sample ◽  
K Band

We have investigated the Tully-Fisher relation for Polar Ring Galaxies (PRGs), based on near infrared, optical and Hi data available for a sample of these peculiar objects. The total K-band luminosity, which mainly comes from the central host galaxy, and the measured Hi linewidth at 20% of the peak line flux density, which traces the potential in the polar plane, place most polar rings of the sample far from the Tully-Fisher relation defined for spiral galaxies, with many PRGs showing larger Hi line-widths than expected for the observed K band luminosity. This result is confirmed by a larger sample of objects, based on B-band data. This observational evidence may be related to the dark halo shape and orientation in these systems, which we study by numerical modeling of PRG formation and dynamics: the larger rotation velocities observed in PRGs can be explained by a flattened polar halo, aligned with the polar ring.

scholarly journals The radio-loud narrow-line Seyfert 1 galaxy 1H 0323+342 in a galaxy merger

2020 ◽  
Vol 496 (2) ◽  
pp. 1757-1765 ◽  
Author(s):  
Akihiro Doi ◽  
Motoki Kino ◽  
Nozomu Kawakatu ◽  
Kazuhiro Hada
Keyword(s):  
Black Holes ◽  
Near Infrared ◽  
Gamma Ray ◽  
Linear Structure ◽  
Seyfert Galaxies ◽  
Mass Function ◽  
High Mass ◽  
Host Galaxy ◽  
Supporting Evidence ◽  
Narrow Line

ABSTRACT The supermassive black holes (SMBHs) of narrow-line Seyfert 1 galaxies (NLS1s) are at the lower end of the mass function of active galactic nuclei (AGNs) and reside preferentially in late-type host galaxies with pseudobulges, which are thought to be formed by internal secular evolution. On the other hand, the population of radio-loud NLS1s presents a challenge for the relativistic jet paradigm, which states that powerful radio jets are associated exclusively with very high mass SMBHs in elliptical hosts, which are built up through galaxy mergers. We investigated distorted radio structures associated with the nearest gamma-ray-emitting, radio-loud NLS1, 1H 0323+342. This provides supporting evidence for the merger hypothesis based on past optical/near-infrared observations of its host galaxy. The anomalous radio morphology consists of two different structures: the inner curved structure of the currently active jet and an outer linear structure of low-brightness relics. Such coexistence might be indicative of the stage of an established black hole binary with precession before the black holes coalesce in the galaxy merger process. 1H 0323+342 and other radio-loud NLS1s under galaxy interactions may be extreme objects on the evolutionary path from radio-quiet NLS1s to normal Seyfert galaxies with larger SMBHs in classical bulges through mergers and merger-induced jet phases.

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