Studies of Star-Forming Galaxies at High-Z. II: The First Results of Cosmos K Band Survey

2001 ◽  
pp. 367-367
Author(s):  
D. Cristóbal ◽  
M. Prieto ◽  
R. Guzmán ◽  
M. Balcells ◽  
J. Acosta ◽  
...  
Keyword(s):  
Star Forming ◽  
First Results ◽  
Band Survey ◽  
K Band

scholarly journals NIR Follow-Up of the VVDS 02hr Field: First Results

2006 ◽  
Vol 2 (S235) ◽  
pp. 432-437
Author(s):  
S. Temporin ◽  
A. Iovino ◽  
H. J. McCracken ◽  
M. Bolzonella ◽  
M. Scodeggio ◽  
...  
Keyword(s):  
Near Infrared ◽  
High Redshift ◽  
First Results ◽  
Band Survey ◽  
K Band

AbstractWe present a new K-band survey covering 623 arcmin2 in the VVDS 0226-0430 deep field down to a limiting magnitude KVega ≤ 20.5. We use the spectroscopic sample extracted from this new K-band catalogue to assess the effectiveness of optical-near infrared color selections in identifying extreme classes of objects at high redshift.

scholarly journals Probing the Redshift Desert Using the Gemini Deep Deep Survey: Observing Galaxy Mass Assembly at z > 1

2005 ◽  
Vol 216 ◽  
pp. 390-397
Author(s):  
Karl Glazebrook ◽  
Keyword(s):  
Spectroscopic Studies ◽  
Star Forming ◽  
Hubble Sequence ◽  
First Results ◽  
Deep Survey ◽  
Redshift Survey ◽  
Mass Assembly ◽  
Galaxy Assembly ◽  
First Time ◽  
The Universe

The aim of the Gemini Deep Deep Survey is to push spectroscopic studies of complete galaxy samples (both red and blue objects) significantly beyond z = 1; this is the redshift where the current Hubble sequence of ellipticals and spirals is already extant. In the Universe at z = 2 the only currently spectroscopically confirmed galaxies are blue, star-forming and of fragmented morphology. Exploring this transition means filling the ‘redshift desert’ 1 < z < 2 where there is a dearth of spectroscopic measurements. To do this we need to secure redshifts of the oldest, reddest galaxies (candidate ellipticals) beyond z > 1 which has led us to carry out the longest exposure redshift survey ever done: 100 ksec spectroscopic MOS exposures with GMOS on Gemini North. We have developed an implementation of the CCD “nod & shuffle” technique to ensure precise sky-subtraction in these ultra-deep exposures. At the halfway mark the GDDS now has ∼ 36 galaxies in the redshift desert 1.2 < z < 2 extending up to z = 1.97 and I < 24.5 with secure redshifts based on weak rest-frame UV absorption features complete for both red, old objects and young, blue objects. The peak epoch of galaxy assembly is now being probed by direct spectroscopic investigation for the first time. on behalf of the GDDS team I present our first results on the properties of galaxies in the ‘redshift desert’.

scholarly journals An imaging K-band survey – II. The redshift survey and galaxy evolution in the infrared

1995 ◽  
Vol 275 (1) ◽  
pp. 169-184 ◽  
Author(s):  
Karl Glazebrook ◽  
J. A. Peacock ◽  
L. Miller ◽  
C. A. Collins
Keyword(s):  
Galaxy Evolution ◽  
Redshift Survey ◽  
Band Survey ◽  
K Band

scholarly journals MUSE Analysis of Gas around Galaxies (MAGG) – I: Survey design and the environment of a near pristine gas cloud at z ≈ 3.5

2019 ◽  
Vol 491 (2) ◽  
pp. 2057-2074 ◽  
Author(s):  
Emma K Lofthouse ◽  
Michele Fumagalli ◽  
Matteo Fossati ◽  
John M O’Meara ◽  
Michael T Murphy ◽  
...  
Keyword(s):  
Survey Design ◽  
Strong Absorption ◽  
Nearby Galaxy ◽  
Star Forming ◽  
Very Large Telescope ◽  
The Galaxy ◽  
First Results ◽  
Statistical Sample ◽  
Galaxy Population ◽  
Gas Cloud

ABSTRACT We present the design, methods, and first results of the MUSE Analysis of Gas around Galaxies (MAGG) survey, a large programme on the Multi-Unit Spectroscopic Explorer (MUSE) instrument at the Very Large Telescope (VLT), which targets 28 z &gt; 3.2 quasars to investigate the connection between optically thick gas and galaxies at z ∼ 3–4. MAGG maps the environment of 52 strong absorption line systems at z ≳ 3, providing the first statistical sample of galaxies associated with gas-rich structures in the early Universe. In this paper, we study the galaxy population around a very metal poor gas cloud at z ≈ 3.53 towards the quasar J124957.23−015928.8. We detect three Lyα emitters within $\lesssim 200~\rm km~s^{-1}$ of the cloud redshift, at projected separations $\lesssim 185~\rm ~kpc$ (physical). The presence of star-forming galaxies near a very metal-poor cloud indicates that metal enrichment is still spatially inhomogeneous at this redshift. Based on its very low metallicity and the presence of nearby galaxies, we propose that the most likely scenario for this Lyman Limit System (LLS) is that it lies within a filament which may be accreting on to a nearby galaxy. Taken together with the small number of other LLSs studied with MUSE, the observations to date show a range of different environments near strong absorption systems. The full MAGG survey will significantly expand this sample and enable a statistical analysis of the link between gas and galaxies to pin down the origin of these diverse environments at z ≈ 3–4.

Sardinia Radio Telescope (SRT) observations of Local Group dwarf galaxies

2017 ◽  
Vol 13 (S336) ◽  
pp. 109-112
Author(s):  
A. Tarchi ◽  
P. Castangia ◽  
G. Surcis ◽  
A. Brunthaler ◽  
K. M. Menten ◽  
...  
Keyword(s):  
Radio Telescope ◽  
Local Group ◽  
Dwarf Galaxies ◽  
Radio Continuum ◽  
Maser Emission ◽  
Star Forming ◽  
Star Forming Regions ◽  
First Results ◽  
Ngc 6822 ◽  
Almost All

AbstractThe dwarf galaxies in the Local Group (LG) reveal a surprising amount of spatial structuring. In particular, almost all non-satellite dwarfs belong to one of two planes that show a very pronounced symmetry. In order to determine if these structures in the LG are dynamically stable or, alternatively, if they only represent transient alignments, proper motion measurements of these galaxies are required. A viable method to derive proper motions is offered by VLBI studies of 22-GHz water (and 6.7-GHz methanol) maser lines in star-forming regions.In 2016, in the framework of the Early Science Program of the Sardinia Radio Telescope (SRT), we have conducted an extensive observational campaign to map the entire optical body of all the LG dwarf galaxies that belong to the two planes, at C and K band, in a search for methanol and water maser emission.Here, we outline the project and present its first results on 3 targets, NGC 6822, IC 1613, and WLM. While no luminous maser emission has been detected in these galaxies, a number of interesting weaker detections has been obtained, associated with particularly active star forming regions. In addition, we have produced deep radio continuum maps for these galaxies, aimed at investigating their star forming activity and providing an improved assessment of star formation rates in these galaxies.

scholarly journals Cosmic ray feedback in the FIRE simulations: constraining cosmic ray propagation with GeV γ-ray emission

2019 ◽  
Vol 488 (3) ◽  
pp. 3716-3744 ◽  
Author(s):  
T K Chan ◽  
D Kereš ◽  
P F Hopkins ◽  
E Quataert ◽  
K-Y Su ◽  
...  
Keyword(s):  
Transport Coefficients ◽  
Cosmic Ray ◽  
Starburst Galaxies ◽  
Secondary Importance ◽  
Star Forming ◽  
First Results ◽  
Order Of Magnitude ◽  
Γ Ray ◽  
Field Lines ◽  
Formation Efficiency

ABSTRACT We present the implementation and the first results of cosmic ray (CR) feedback in the Feedback In Realistic Environments (FIRE) simulations. We investigate CR feedback in non-cosmological simulations of dwarf, sub-L⋆ starburst, and L⋆ galaxies with different propagation models, including advection, isotropic, and anisotropic diffusion, and streaming along field lines with different transport coefficients. We simulate CR diffusion and streaming simultaneously in galaxies with high resolution, using a two-moment method. We forward-model and compare to observations of γ-ray emission from nearby and starburst galaxies. We reproduce the γ-ray observations of dwarf and L⋆ galaxies with constant isotropic diffusion coefficient $\kappa \sim 3\times 10^{29}\, {\rm cm^{2}\, s^{-1}}$. Advection-only and streaming-only models produce order of magnitude too large γ-ray luminosities in dwarf and L⋆ galaxies. We show that in models that match the γ-ray observations, most CRs escape low-gas-density galaxies (e.g. dwarfs) before significant collisional losses, while starburst galaxies are CR proton calorimeters. While adiabatic losses can be significant, they occur only after CRs escape galaxies, so they are only of secondary importance for γ-ray emissivities. Models where CRs are ‘trapped’ in the star-forming disc have lower star formation efficiency, but these models are ruled out by γ-ray observations. For models with constant κ that match the γ-ray observations, CRs form extended haloes with scale heights of several kpc to several tens of kpc.

scholarly journals Testing the Merger Hypothesis of Powerful Radio Galaxies

1999 ◽  
Vol 186 ◽  
pp. 353-353
Author(s):  
Aaron S. Evans ◽  
D.B. Sanders ◽  
Joseph M. Mazzarella
Keyword(s):  
Radio Galaxies ◽  
Molecular Gas ◽  
Powerful Radio ◽  
Limited Sample ◽  
Star Forming ◽  
Degree Of Irregularity ◽  
K Band

We present K′-band imaging and millimeter (CO) spectroscopy of a 60 and 100 μm flux-limited sample of 35 low redshift, powerful radio galaxies (LzPRGs: P178MHz > 1023.5 W Hz−1 and 0.01 < z < 0.22). These observations are being obtained to test the hypothesis that the radio activity in LzPRGs is triggered by the merger of gas-rich galaxies, as well as to look for evolutionary correlations between the degree of irregularity in the K′-band morphologies, the amount of star-forming molecular gas, and the radio morphologies.

scholarly journals Young stellar clusters triggered by a density wave in NGC 2997

2006 ◽  
Vol 2 (S237) ◽  
pp. 417-417
Author(s):  
P. Grosbøl ◽  
H. Dottori ◽  
R. Gredel
Keyword(s):  
Large Scale ◽  
Near Infrared ◽  
Density Wave ◽  
Star Formation History ◽  
Stellar Clusters ◽  
Star Forming ◽  
Continuous Formation ◽  
Grand Design ◽  
K Band ◽  
Design Spiral

AbstractBright knots along the arms of grand-design spiral galaxies are frequently seen on near-infrared K-band images. To investigate their nature, low resolution K-band spectra of a string of knots in the southern arm of the grand design, spiral galaxy NGC 2997 were obtained with ISAAC/VLT. Most of the knots show strong Brγ emission while some have H2 and HeI emission. A few knots show indications of CO absorption. Their spectra and absolute K magnitudes exceeding -12 mag suggest them to be very compact, young stellar clusters with masses up to 5 × 104 M. The knots' azimuthal distance from the K-band spiral correlates well with their Brγ strength, indicating that they are located inside the co-rotation of the density wave, which triggered them through a large-scale, star-forming front. These relative azimuthal distances suggest an age spread of more than 1.6 Myr, which is incompatible with standard models for an instantaneous star burst. This indicates a more complex star-formation history, such as several bursts or continuous formation.

scholarly journals Radio Sources in the 2dF Galaxy Redshift Survey I. Radio Source Populations

1999 ◽  
Vol 16 (3) ◽  
pp. 247-256 ◽  
Author(s):  
Elaine M. Sadler ◽  
V. J. McIntyre ◽  
C. A. Jackson ◽  
R. D. Cannon
Keyword(s):  
Radio Galaxy ◽  
Radio Continuum ◽  
Radio Sources ◽  
Star Forming ◽  
Sky Survey ◽  
Homogeneous Set ◽  
First Results ◽  
Redshift Survey ◽  
Galaxy Redshift ◽  
Source Populations

AbstractWe present the first results from a study of the radio continuum properties of galaxies in the 2dF Galaxy Redshift Survey, (2dFGRS) based on thirty 2dF fields covering a total area of about 100 deg2. About 1·5% of galaxies with bJ < 19·4 mag. are detected as radio continuum sources in the NRAO VLA Sky Survey (NVSS). Of these, roughly 40% are star-forming galaxies and 60% are active galaxies (mostly low-power radio galaxies and a few Seyferts). The combination of 2dFGRS and NVSS will eventually yield a homogeneous set of around 4000 radio-galaxy spectra, which will be a powerful tool for studying the distribution and evolution of both AGN and starburst galaxies out to z ∼ 0·3.

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