scholarly journals Deep HST Imaging of a Galaxy Cluster at z = 2.40

1996 ◽  
Vol 171 ◽  
pp. 474-475
Author(s):  
Rogier A. Windhorst ◽  
Sam M. Pascarelle ◽  
William C. Keel
Keyword(s):  
Star Formation ◽  
Stellar Population ◽  
Radio Galaxy ◽  
Narrow Band ◽  
Galaxy Cluster ◽  
Narrow Line ◽  
Color Plate ◽  
Band Emission ◽  
Physical Scale ◽  
Line Galaxy

We present a 67-orbit HST/WFPC2 exposure on the weak radio galaxy 53W002 at z=2.390 and its surrounding cluster. Color Plate 1 shows 12 orbits in IF814W & VF606W, and 24 in BF450W. Potential cluster members were identified through 15 orbits in F410M, optimized for narrow-band searches for compact Lyα objects at z≃2.4 (P96), and confirmed through spectroscopy (W91, P96); 16 candidates were found with significant narrow-band emission in F410M: 4 out of 5 had a confirming MMT spectroscopic redshift at z≃2.40 (P96). All are located within 60″ from 53W002, or ∼ 0.24h–1100 Mpc (qo=0.5) at z ≃2.4, the physical scale of a group or small galaxy cluster. One object contains a weak (variable) AGN, another is a merger with two companions. Their underlying young stellar population is very compact, with rh.l. ≃0.2″ (≃ 0.8h–1100 kpc), and considerably fainter than the L∗-value at z∼2.4, implying sub-galactic sized objects. These results may explain why ground-based Lya searches for PG's have been largely unsuccessful. The narrow-line galaxy 53W002 was imaged in the PC at ∼0.07″ FWHM (WK95, see also W94). Its AGN component is ≤ 20±4% of the total continuum, surrounded by an extended r1/4-envelope with rh.l. ≃1.1″ (4.3 kpc), and has an SED of ∼0.3 Gyr in the center to ∼0.5-1.0 Gyr at ∼4 kpc. A one-sided cloud is seen ∼1.8 kpc West, ∼0.3 mag bluer than the SED, aligned with the radio source and its Ly-α cloud, presumably weak scattered AGN light, and/or jet-induced star-formation.

scholarly journals Dust and star formation in the centre of NGC 3311

2020 ◽  
Vol 643 ◽  
pp. A119 ◽  
Author(s):  
T. Richtler ◽  
M. Hilker ◽  
M. Arnaboldi ◽  
C. E. Barbosa
Keyword(s):  
Star Formation ◽  
Emission Line ◽  
Globular Clusters ◽  
Stellar Population ◽  
Line Emission ◽  
Galaxy Cluster ◽  
Emission Lines ◽  
Strong Line ◽  
Rotating Disc ◽  
Neutral Gas

Context. NGC 3311 is the central galaxy of the Hydra I galaxy cluster. It has a hot interstellar medium and hosts a central dust lane with emission lines. These dust lanes are frequent in elliptical galaxies, but the case of NGC 3311 might be particularly interesting for problems of dust lifetime and the role of cool gas in the central parts. Aims. We aim to use archival HST images and MUSE data to investigate the central dust structure of NGC 3311. Methods. We used the tool PyParadise to model the stellar population and extract the emission lines. Results. The HST/ACS colour map reveals the known dust structures, but also blue spots, which are places of strong line emission. A dusty “mini-jet” emanates from the centre. The distribution of the emission line gas matches the dust silhouette almost exactly. Close to the brightest Hα emission, the ratio [NII]/Hα resembles that of HII-regions; in the outer parts, [NII] gets stronger and is similar to LINERLow-ionization nuclear emission-line region -like spectra. The gas kinematics is consistent with that of a rotating disc. The Doppler shifts of the strongest line emissions, which indicate the areas of highest star formation activity, smoothly fit into the disc symmetry. The metallicity is supersolar. The presence of neutral gas is indicated by the fit residuals of the stellar NaI D absorption line, which we interpret as interstellar absorption. We estimate the mass of the neutral gas to be of the order of the X-ray mass. The dynamical mass infers a stellar population of intermediate age, whose globular clusters have already been identified. Conclusions. Our findings can be harmonised in a scenario in which the star formation is triggered by the accretion of cold gas onto a pre-existing gas/dust disc or ring. Newly produced dust then contributes to the longevity of the dust.

Infrared Studies of the Young Stellar Population of 30 Doradus

1980 ◽  
Vol 4 (1) ◽  
pp. 90-92
Author(s):  
P. J. McGregor ◽  
A. R. Hyland
Keyword(s):  
Star Formation ◽  
Stellar Population ◽  
Cluster Formation ◽  
Large Magellanic Cloud ◽  
Magellanic Cloud ◽  
Formation Processes ◽  
Excellent Opportunity ◽  
Infrared Studies ◽  
30 Doradus

The 30 Doradus region offers an excellent opportunity to study cluster formation processes and recent star formation in the Large Magellanic Cloud.

scholarly journals HI Distribution in Extreme Dwarf Irregulars and Dwarf Spheroidals

1998 ◽  
Vol 11 (1) ◽  
pp. 121-122
Author(s):  
Claude Carignan
Keyword(s):  
Star Formation ◽  
Stellar Population ◽  
Large Fraction ◽  
Dwarf Spheroidal Galaxies ◽  
Irregular Galaxies ◽  
Single Burst ◽  
Dwarf Spheroidals ◽  
Dwarf Irregular Galaxies ◽  
Spheroidal Galaxies

Recent studies (Puche & Westpfahl 1994, Young & Lo 1996) have shown that the distribution of HI in some extreme low luminosity dwarf irregular galaxies (e.g. M81dwA, Holmberg I, Leo A) tends to have a ring-like (or shell-like) distribution which suggests that a single burst of star formation could expell most of the remaining ISM (or at least a large fraction of it) from the system. In view of this, Puche & Westpfahl (1994) suggested that in dwarf spheroidal galaxies, the HI should be found at large radii since no young stellar population is observed in most of them.

scholarly journals The environmental effect on galaxy evolution: Cl J1449 + 0856 at z = 1.99

2020 ◽  
Vol 15 (S359) ◽  
pp. 170-172
Author(s):  
Rosemary T. Coogan ◽  
E. Daddi ◽  
R. Gobat ◽  
M. T. Sargent
Keyword(s):  
Star Formation ◽  
Galaxy Evolution ◽  
Environmental Effect ◽  
Galaxy Cluster ◽  
Molecular Gas ◽  
The Core

AbstractThis work focuses on understanding the formation of the first massive, passive galaxies in clusters, as a first step to the development of environmental trends seen at low redshift. Cl J1449 + 0856 is an excellent case to study this - a galaxy cluster at redshift z = 1.99 that already shows evidence of a virialised atmosphere. Here we highlight two recent results: the discovery of merger-driven star formation and highly-excited molecular gas in galaxies at the core of Cl J1449, along with the lowest-mass Sunyaev-Zel’dovich detection to date.

scholarly journals A z = 2.5 protocluster associated with the radio galaxy MRC 2104-242: star formation and differing mass functions in dense environments

2014 ◽  
Vol 440 (4) ◽  
pp. 3262-3274 ◽  
Author(s):  
E. A. Cooke ◽  
N. A. Hatch ◽  
S. I. Muldrew ◽  
E. E. Rigby ◽  
J. D. Kurk
Keyword(s):  
Star Formation ◽  
Radio Galaxy ◽  
Mass Functions

scholarly journals Star-formation in NGC 4038/4039 from broad and narrow band photometry: cluster destruction?

2005 ◽  
Vol 443 (1) ◽  
pp. 41-60 ◽  
Author(s):  
S. Mengel ◽  
M. D. Lehnert ◽  
N. Thatte ◽  
R. Genzel
Keyword(s):  
Star Formation ◽  
Narrow Band

scholarly journals Planck’s dusty GEMS

2018 ◽  
Vol 620 ◽  
pp. A60 ◽  
Author(s):  
R. Cañameras ◽  
N. P. H. Nesvadba ◽  
M. Limousin ◽  
H. Dole ◽  
R. Kneissl ◽  
...  
Keyword(s):  
Star Formation ◽  
Near Infrared ◽  
Infrared Imaging ◽  
High Redshift ◽  
Dust Emission ◽  
Galaxy Cluster ◽  
Star Forming ◽  
The Galaxy ◽  
Mass Outflow ◽  
Gas Accretion

We report the discovery of a molecular wind signature from a massive intensely star-forming clump of a few 109 M⊙, in the strongly gravitationally lensed submillimeter galaxy “the Emerald” (PLCK_G165.7+49.0) at z = 2.236. The Emerald is amongst the brightest high-redshift galaxies on the submillimeter sky, and was initially discovered with the Planck satellite. The system contains two magnificient structures with projected lengths of 28.5″ and 21″ formed by multiple, near-infrared arcs, falling behind a massive galaxy cluster at z = 0.35, as well as an adjacent filament that has so far escaped discovery in other wavebands. We used HST/WFC3 and CFHT optical and near-infrared imaging together with IRAM and SMA interferometry of the CO(4–3) line and 850 μm dust emission to characterize the foreground lensing mass distribution, construct a lens model with LENSTOOL, and calculate gravitational magnification factors between 20 and 50 in most of the source. The majority of the star formation takes place within two massive star-forming clumps which are marginally gravitationally bound and embedded in a 9 × 1010 M⊙, fragmented disk with 20% gas fraction. The stellar continuum morphology is much smoother and also well resolved perpendicular to the magnification axis. One of the clumps shows a pronounced blue wing in the CO(4–3) line profile, which we interpret as a wind signature. The mass outflow rates are high enough for us to suspect that the clump might become unbound within a few tens of Myr, unless the outflowing gas can be replenished by gas accretion from the surrounding disk. The velocity offset of –200 km s−1 is above the escape velocity of the clump, but not that of the galaxy overall, suggesting that much of this material might ultimately rain back onto the galaxy and contribute to fueling subsequent star formation.

scholarly journals Radio Loud Far-Infrared Galaxies

1990 ◽  
Vol 124 ◽  
pp. 309-314 ◽  
Author(s):  
Arjun Dey ◽  
Wil van Breugel ◽  
Joseph C. Shields
Keyword(s):  
Star Formation ◽  
Radio Emission ◽  
Point Source ◽  
Optical Imaging ◽  
Radio Galaxy ◽  
Far Infrared ◽  
Infrared Galaxies ◽  
Galaxy Interactions ◽  
First Results ◽  
Radio Survey

AbstractWe present the first results of a multiwavelength study of IRAS galaxies with excess radio emission. The sample was selected by cross-correlating the IRAS Faint Source Survey (for |b| ≥ 50°) and the Point Source Catalogue (for 10° < |b| < 50°) with the Texas radio survey. Recent optical (imaging and spectroscopic) and radio (VLA) observations are discussed. These observations will be used to investigate possible connections between radio galaxy activity, star formation and galaxy interactions.

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