scholarly journals VLA imaging of the XMM-LSS/VIDEO deep field at 1–2 GHz

2020 ◽  
Vol 496 (3) ◽  
pp. 3469-3481
Author(s):  
I Heywood ◽  
C L Hale ◽  
M J Jarvis ◽  
S Makhathini ◽  
J A Peters ◽  
...  

ABSTRACT Modern radio telescopes are routinely reaching depths where normal star-forming galaxies are the dominant observed population. Realizing the potential of radio as a tracer of star formation and black hole activity over cosmic time involves achieving such depths over representative volumes, with radio forming part of a larger multiwavelength campaign. In pursuit of this, we used the Karl G. Jansky Very Large Array (VLA) to image ∼5 deg2 of the VIDEO/XMM-LSS extragalactic deep field at 1–2 GHz. We achieve a median depth of 16 µJy beam−1 with an angular resolution of 4.5 arcsec. Comparisons with existing radio observations of XMM-LSS showcase the improved survey speed of the upgraded VLA: we cover 2.5 times the area and increase the depth by ∼20 per cent in 40 per cent of the time. Direction-dependent calibration and wide-field imaging were required to suppress the error patterns from off-axis sources of even modest brightness. We derive a catalogue containing 5762 sources from the final mosaic. Sub-band imaging provides in-band spectral indices for 3458 (60 per cent) sources, with the average spectrum becoming flatter than the canonical synchrotron slope below 1 mJy. Positional and flux density accuracy of the observations, and the differential source counts are in excellent agreement with those of existing measurements. A public release of the images and catalogue accompanies this article.

2007 ◽  
Author(s):  
S. A. Rinehart ◽  
T. Armstrong ◽  
Bradley J. Frey ◽  
J. Jung ◽  
J. Kirk ◽  
...  

2007 ◽  
Vol 3 (S242) ◽  
pp. 230-231
Author(s):  
James R. Forster

AbstractGalactic Giant Molecular Cloud (GMC) complexes are among the largest objects in the sky. In order to get the full picture of Galactic star formation a large field of view is important. The Allen Telescope Array (ATA) is the first of a new generation of large-N, small-D radio telescopes designed to provide high quality images on large angular scales. We present here the first wide field images of GMCs made with the ATA.


2003 ◽  
Vol 211 ◽  
pp. 81-82 ◽  
Author(s):  
César Briceño ◽  
Kevin L. Luhman ◽  
Lee Hartmann ◽  
John R. Stauffer ◽  
J. Davy Kirkpatrick

We present the results of a deep, optical/IR wide field imaging survey of selected fields in the nearby (d~ 140 pc) Taurus star-forming region. We report the discovery of 9 new members with spectral types M5.75–M9.5. We derive an Initial Mass Function encompassing 54% of the known members in Taurus. Comparison with dense regions like the Trapezium Cluster in Orion shows that Taurus has produced x2 less brown dwarfs. We suggest that the lower frequency of brown dwarfs in Taurus may result from the low-density star-forming environment, leading to larger minimum Jeans masses.


2016 ◽  
Vol 11 (S321) ◽  
pp. 211-213
Author(s):  
F. Annibali ◽  
M. Tosi ◽  
A. Aloisi ◽  
M. Bellazzini ◽  
A. Buzzoni ◽  
...  

AbstractWe present two pilot studies for the search and characterization of accretion events in star-forming dwarf galaxies. Our strategy consists of two complementary approaches: i) the direct search for stellar substructures around dwarf galaxies through deep wide-field imaging, and ii) the characterization of the chemical properties in these systems up to large galacto-centric distances. We show our results for two star-forming dwarf galaxies, the starburst irregular NGC 4449, and the extremely metal-poor dwarf DDO 68.


2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Martin Schmidt ◽  
Adam C. Hundahl ◽  
Henrik Flyvbjerg ◽  
Rodolphe Marie ◽  
Kim I. Mortensen

AbstractUntil very recently, super-resolution localization and tracking of fluorescent particles used camera-based wide-field imaging with uniform illumination. Then it was demonstrated that structured illuminations encode additional localization information in images. The first demonstration of this uses scanning and hence suffers from limited throughput. This limitation was mitigated by fusing camera-based localization with wide-field structured illumination. Current implementations, however, use effectively only half the localization information that they encode in images. Here we demonstrate how all of this information may be exploited by careful calibration of the structured illumination. Our approach achieves maximal resolution for given structured illumination, has a simple data analysis, and applies to any structured illumination in principle. We demonstrate this with an only slightly modified wide-field microscope. Our protocol should boost the emerging field of high-precision localization with structured illumination.


2020 ◽  
Vol 499 (3) ◽  
pp. 4068-4081 ◽  
Author(s):  
Ting-Wen Wang ◽  
Tomotsugu Goto ◽  
Seong Jin Kim ◽  
Tetsuya Hashimoto ◽  
Denis Burgarella ◽  
...  

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.


2021 ◽  
Vol 2 (2) ◽  
pp. 100542
Author(s):  
Taiga Takahashi ◽  
Hong Zhang ◽  
Kohei Otomo ◽  
Yosuke Okamura ◽  
Tomomi Nemoto

Sign in / Sign up

Export Citation Format

Share Document