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 > 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.

scholarly journals The MUSE Ultra Deep Field (MUDF). II. Survey design and the gaseous properties of galaxy groups at 0.5 < z < 1.5

2019 ◽  
Vol 490 (1) ◽  
pp. 1451-1469 ◽  
Author(s):  
M Fossati ◽  
M Fumagalli ◽  
E K Lofthouse ◽  
V D’Odorico ◽  
E Lusso ◽  
...  
Keyword(s):  
Dynamic Range ◽  
Survey Design ◽  
High Resolution Spectroscopy ◽  
Isolated Galaxies ◽  
Very Large Telescope ◽  
The Galaxy ◽  
First Results ◽  
High Fraction ◽  
Galaxy Environment ◽  
Cool Gas

ABSTRACT We present the goals, design, and first results of the MUSE Ultra Deep Field (MUDF) survey, a large programme using the Multi Unit Spectroscopic Explorer (MUSE) instrument at the ESO Very Large Telescope. The MUDF survey is collecting ≈150 h on-source of integral field optical spectroscopy in a 1.5 × 1.2 arcmin2 region which hosts several astrophysical structures along the line of sight, including two bright z ≈ 3.2 quasars with close separation (≈500 kpc). Following the description of the data reduction procedures, we present the analysis of the galaxy environment and gaseous properties of seven groups detected at redshifts 0.5 &lt; z &lt; 1.5, spanning a large dynamic range in halo mass, $\log (M_h/\rm {M_\odot }) \approx 11 - 13.5$. For four of the groups, we find associated Mg ii absorbers tracing cool gas in high-resolution spectroscopy of the two quasars, including one case of correlated absorption in both sightlines at distance ≈480 kpc. The absorption strength associated with the groups is higher than what has been reported for more isolated galaxies of comparable mass and impact parameters. We do not find evidence for widespread cool gas giving rise to strong absorption within these groups. Combining these results with the distribution of neutral and ionized gas seen in emission in lower redshift groups, we conclude that gravitational interactions in the group environment strip gas from the galaxy haloes into the intragroup medium, boosting the cross-section of cool gas and leading to the high fraction of strong Mg ii absorbers that we detect.

scholarly journals The Bimodality of Galaxy Populations Revisited Through Spectral Synthesis

2006 ◽  
Vol 2 (S235) ◽  
pp. 139-139
Author(s):  
L. Sodré ◽  
A. Mateus ◽  
R. Cid Fernandes ◽  
G. Stasińska ◽  
W. Schoenell ◽  
...  
Keyword(s):  
Galaxy Formation ◽  
Spectral Synthesis ◽  
Synthesis Method ◽  
Local Universe ◽  
Massive Galaxies ◽  
Star Forming ◽  
The Galaxy ◽  
Galaxy Populations ◽  
Galaxy Population ◽  
Stellar Masses

AbstractWe revisit the bimodality of the galaxy population seen in the local universe. We address this issue in terms of physical properties of galaxies, such as mean stellar ages and stellar masses, derived from the application of a spectral synthesis method to galaxy spectra from the SDSS. We show that the mean light-weighted stellar age of galaxies presents the best description of the bimodality seen in the galaxy population. The stellar mass has an additional role since most of the star-forming galaxies present in the local universe are low-mass galaxies. Our results give support to the existence of a ‘downsizing’ in galaxy formation, where nowadays massive galaxies tend to have stellar populations older than those found in less massive objects.

scholarly journals Cepheids in the Nearby Galaxy IC 1613

2000 ◽  
Vol 176 ◽  
pp. 157-160
Author(s):  
E. Antonello ◽  
L. Mantegazza ◽  
D. Fugazza ◽  
M. Bossi ◽  
S. Covino
Keyword(s):  
Magellanic Clouds ◽  
Light Curves ◽  
Nearby Galaxy ◽  
Short Discussion ◽  
The Galaxy ◽  
First Results ◽  
First Time

AbstractA summary of the first results of a search for Cepheids in IC 1613 is reported along with a short discussion of the adopted technique, a comparison of the characteristics of Cepheid light curves in the Galaxy, Magellanic Clouds and IC 1613, and a possible application for a P–L relation derivation. First overtone Cepheids have been identified for the first time in a galaxy farther than the Magellanic Clouds.

scholarly journals Redshift measurement through star formation

2019 ◽  
Vol 629 ◽  
pp. A7
Author(s):  
Mikkel O. Lindholmer ◽  
Kevin A. Pimbblet
Keyword(s):  
Star Formation ◽  
Galaxy Clusters ◽  
Main Sequence ◽  
Formation Rate ◽  
Sloan Digital Sky Survey ◽  
X Ray ◽  
Star Forming ◽  
Sky Survey ◽  
The Galaxy ◽  
Galaxy Population

In this work we use the property that, on average, star formation rate increases with redshift for objects with the same mass – the so called galaxy main sequence – to measure the redshift of galaxy clusters. We use the fact that the general galaxy population forms both a quenched and a star-forming sequence, and we locate these ridges in the SFR–M⋆ plane with galaxies taken from the Sloan Digital Sky Survey in discrete redshift bins. We fitted the evolution of the galaxy main sequence with redshift using a new method and then subsequently apply our method to a suite of X-ray selected galaxy clusters in an attempt to create a new distance measurement to clusters based on their galaxy main sequence. We demonstrate that although it is possible in several galaxy clusters to measure the main sequences, the derived distance and redshift from our galaxy main sequence fitting technique has an accuracy of σz = ±0.017 ⋅ (z + 1) and is only accurate up to z ≈ 0.2.

scholarly journals Study of a Complete Sample of Hα Emission–Line Galaxies from the UCM Survey

1996 ◽  
Vol 171 ◽  
pp. 380-380 ◽  
Author(s):  
J. Gallego ◽  
J. Zamorano ◽  
M. Rego ◽  
A.G. Vitores ◽  
O. Alonso
Keyword(s):  
Star Formation ◽  
Emission Line ◽  
Energy Output ◽  
University Of Michigan ◽  
Complete Sample ◽  
Star Forming ◽  
The Galaxy ◽  
Hα Emission ◽  
Emission Line Galaxies ◽  
Galaxy Population

The Universidad Complutense de Madrid survey is a long-term project with the aim of finding and analyzing star forming galaxies using the Hα line as the tracer for star formation processes. In order to obtain a representative and complete sample of the population detected, spectroscopic observations were carried out for the full sample of Hα emission-line galaxy (ELG) candidates of the UCM lists 1 and 2. The ELGs types most commonly found (47%) are intermediate to low-luminosity objects with a very intense star-formation region which dominates the optical energy output of the galaxy. This kind of ELGs is similar to the galaxy population detected in the blue objective-prism surveys. And what is more important, a second population (43%) of star-forming galaxies with low ionization or high extinction properties has been found. This ELGs group is detected neither in the blue (University of Michigan survey, Case survey) nor in other surveys (Kiso, IRAS, Markarian) using other selection techniques.

scholarly journals Milky Way analogues in MaNGA: multiparameter homogeneity and comparison to the Milky Way

2019 ◽  
Vol 491 (3) ◽  
pp. 3672-3701 ◽  
Author(s):  
N Boardman ◽  
G Zasowski ◽  
A Seth ◽  
J Newman ◽  
B Andrews ◽  
...  
Keyword(s):  
Galaxy Evolution ◽  
Milky Way ◽  
Central Star ◽  
Stellar Kinematics ◽  
Star Forming ◽  
Wide Range ◽  
The Galaxy ◽  
Central Regions ◽  
Galaxy Population ◽  
Stellar Masses

ABSTRACT The Milky Way provides an ideal laboratory to test our understanding of galaxy evolution, owing to our ability to observe our Galaxy over fine scales. However, connecting the Galaxy to the wider galaxy population remains difficult, due to the challenges posed by our internal perspective and to the different observational techniques employed. Here, we present a sample of galaxies identified as Milky Way analogues on the basis of their stellar masses and bulge-to-total ratios, observed as part of the Mapping Nearby Galaxies at Apache Point Observatory survey. We analyse the galaxies in terms of their stellar kinematics and populations as well as their ionized gas contents. We find our sample to contain generally young stellar populations in their outskirts. However, we find a wide range of stellar ages in their central regions, and we detect central active galactic nucleus-like or composite-like activity in roughly half of the sample galaxies, with the other half consisting of galaxies with central star-forming emission or emission consistent with old stars. We measure gradients in gas metallicity and stellar metallicity that are generally flatter in physical units than those measured for the Milky Way; however, we find far better agreement with the Milky Way when scaling gradients by galaxies’ disc scale lengths. From this, we argue much of the discrepancy in metallicity gradients to be due to the relative compactness of the Milky Way, with differences in observing perspective also likely to be a factor.

scholarly journals Modelling a bright z = 6 galaxy at the faint end of the AGN luminosity function

2020 ◽  
Vol 494 (3) ◽  
pp. 3453-3463
Author(s):  
Maxime Trebitsch ◽  
Marta Volonteri ◽  
Yohan Dubois
Keyword(s):  
Black Hole ◽  
High Redshift ◽  
Galactic Nuclei ◽  
Stellar Populations ◽  
Star Forming ◽  
Relative Contribution ◽  
Lyman Break Galaxies ◽  
The Galaxy ◽  
Galaxy Population ◽  
High Redshift Universe

ABSTRACT Recent deep surveys have unravelled a population of faint active galactic nuclei (AGNs) in the high-redshift Universe, leading to various discussions on their nature and their role during the Epoch of Reionization. We use cosmological radiation hydrodynamics simulations of a bright galaxy at z ∼ 6 (${M_\star } \gtrsim 10^{10}\, {\rm M}_{\odot }$) hosting an actively growing supermassive black hole to study the properties of these objects. In particular, we study how the black hole and the galaxy coevolve and what is the relative contribution of the AGNs and of the stellar populations to the luminosity budget of the system. We find that the feedback from the AGN has no strong effect on the properties of the galaxy, and does not increase the total ionizing luminosity of the host. The average escape fraction of our galaxy is around $f_{\rm esc} \sim 5{{\ \rm per\ cent}}$. While our galaxy would be selected as an AGN in deep X-ray surveys, most of the ultraviolet (UV) luminosity is originating from stellar populations. This confirms that there is a transition in the galaxy population from star-forming galaxies to quasar hosts, with bright Lyman-break galaxies with MUV around −22 falling in the overlap region. Our results also suggest that faint AGNs do not contribute significantly to reionizing the Universe.

scholarly journals Quasar Sightline and Galaxy Evolution (QSAGE) survey – I. The galaxy environment of O vi absorbers up to z = 1.4 around PKS 0232−04

2019 ◽  
Vol 486 (1) ◽  
pp. 21-41 ◽  
Author(s):  
R M Bielby ◽  
J P Stott ◽  
F Cullen ◽  
T M Tripp ◽  
J N Burchett ◽  
...  
Keyword(s):  
Galaxy Evolution ◽  
Near Infrared ◽  
Hubble Space Telescope ◽  
High Redshift ◽  
Star Forming ◽  
The Galaxy ◽  
Circumgalactic Medium ◽  
Galaxy Environment ◽  
Using Data ◽  
Galaxy Population

ABSTRACT We present the first results from a study of O vi absorption around galaxies at z &lt; 1.44 using data from a near-infrared grism spectroscopic Hubble Space Telescope Large Programme, the Quasar Sightline and Galaxy Evolution (QSAGE) survey. QSAGE is the first grism galaxy survey to focus on the circumgalactic medium at z ∼ 1, providing a blind survey of the galaxy population. The galaxy sample is H α flux limited (f(H α) &gt; 2 × 10−17 erg s−1 cm−2) at 0.68 &lt; z &lt; 1.44, corresponding to ≳0.2–0.8 M⊙ yr−1. In this first of 12 fields, we combine the galaxy data with high-resolution STIS and COS spectroscopy of the background quasar to study O vi in the circumgalactic medium. At z ∼ 1, we find O vi absorption systems up to b ∼ 350 kpc (∼4Rvir) from the nearest detected galaxy. Further, we find ${\sim }50{{\ \rm per\ cent}}$ of ≳1 M⊙ yr−1 star-forming galaxies within 2Rvir show no associated O vi absorption to a limit of at least N(O vi) = 1013.9 cm−2. That we detect O vi at such large distances from galaxies and that a significant fraction of star-forming galaxies show no detectable O vi absorption disfavours outflows from ongoing star formation as the primary medium traced by these absorbers. Instead, by combining our own low- and high-redshift data with existing samples, we find tentative evidence for many strong (N(O vi) &gt; 1014 cm−2) O vi absorption systems to be associated with M⋆ ∼ 109.5–10 M⊙ mass galaxies (Mhalo ∼ 1011.5–12 M⊙ dark matter haloes), and infer that they may be tracing predominantly collisionally ionized gas within the haloes of such galaxies.

scholarly journals RadioAstron space-VLBI project: studies of masers in star forming regions of our Galaxy and megamasers in external galaxies

2017 ◽  
Vol 13 (S336) ◽  
pp. 417-421 ◽  
Author(s):  
A. M. Sobolev ◽  
N. N. Shakhvorostova ◽  
A. V. Alakoz ◽  
W. A. Baan
Keyword(s):  
Angular Resolution ◽  
Nearby Galaxy ◽  
Major Step ◽  
Maser Emission ◽  
Star Forming ◽  
Star Forming Regions ◽  
The Galaxy ◽  
External Galaxies ◽  
First Time ◽  
Water Maser

AbstractObservations of the masers in the course of RadioAstron mission yielded detections of fringes for a number of sources in both water and hydroxyl maser transitions. Several sources display numerous ultra-compact details. This proves that implementation of the space VLBI technique for maser studies is possible technically and is not always prevented by the interstellar scattering, maser beaming and other effects related to formation, transfer, and detection of the cosmic maser emission. For the first time, cosmic water maser emission was detected with projected baselines exceeding Earth Diameter. It was detected in a number of star-forming regions in the Galaxy and two megamaser galaxies NGC 4258 and NGC 3079. RadioAstron observations provided the absolute record of the angular resolution in astronomy. Fringes from the NGC 4258 megamaser were detected on baseline exceeding 25 Earth Diameters. This means that the angular resolution sufficient to measure the parallax of the water maser source in the nearby galaxy LMC was directly achieved in the cosmic maser observations. Very compact features with angular sizes about 20\muas\, have been detected in star-forming regions of our Galaxy. Corresponding linear sizes are about 5-10 million kilometers. So, the major step from milli- to micro-arcsecond resolution in maser studies is achieved by the RadioAstron mission. The existence of the features with extremely small angular sizes is established. Further implementations of the space–VLBI maser instrument for studies of the nature of cosmic objects, studies of the interaction of extremely high radiation field with molecular material and studies of the matter on the line of sight are planned.

scholarly journals Ejective and preventative: the IllustrisTNG black hole feedback and its effects on the thermodynamics of the gas within and around galaxies

2020 ◽  
Vol 499 (1) ◽  
pp. 768-792 ◽  
Author(s):  
Elad Zinger ◽  
Annalisa Pillepich ◽  
Dylan Nelson ◽  
Rainer Weinberger ◽  
Rüdiger Pakmor ◽  
...  
Keyword(s):  
Black Hole ◽  
Star Formation ◽  
Massive Galaxies ◽  
Star Forming ◽  
The Galaxy ◽  
Gas Cooling ◽  
Galaxy Population ◽  
Gas Accretion ◽  
Stellar Masses ◽  
Low Entropy

ABSTRACT Supermassive black holes (SMBHs) that reside at the centres of galaxies can inject vast amounts of energy into the surrounding gas and are thought to be a viable mechanism to quench star formation in massive galaxies. Here, we study the $10^{9-12.5}\, \mathrm{M_\odot }$ stellar mass central galaxy population of the IllustrisTNG simulation, specifically the TNG100 and TNG300 volumes at z = 0, and show how the three components – SMBH, galaxy, and circumgalactic medium (CGM) – are interconnected in their evolution. We find that gas entropy is a sensitive diagnostic of feedback injection. In particular, we demonstrate how the onset of the low-accretion black hole (BH) feedback mode, realized in the IllustrisTNG model as a kinetic, BH-driven wind, leads not only to star formation quenching at stellar masses $\gtrsim 10^{10.5}\, \mathrm{M_\odot }$ but also to a change in thermodynamic properties of the (non-star-forming) gas, both within the galaxy and beyond. The IllustrisTNG kinetic feedback from SMBHs increases the average gas entropy, within the galaxy and in the CGM, lengthening typical gas cooling times from $10\!-\!100\, \mathrm{Myr}$ to $1\!-\!10\, \mathrm{Gyr}$, effectively ceasing ongoing star formation and inhibiting radiative cooling and future gas accretion. In practice, the same active galactic nucleus (AGN) feedback channel is simultaneously ‘ejective’ and ‘preventative’ and leaves an imprint on the temperature, density, entropy, and cooling times also in the outer reaches of the gas halo, up to distances of several hundred kiloparsecs. In the IllustrisTNG model, a long-lasting quenching state can occur for a heterogeneous CGM, whereby the hot and dilute CGM gas of quiescent galaxies contains regions of low-entropy gas with short cooling times.

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