scholarly journals Into the Ly α jungle: exploring the circumgalactic medium of galaxies at z ∼ 4−5 with MUSE

2020 ◽  
Vol 493 (4) ◽  
pp. 5336-5356
Author(s):  
Richard M Bielby ◽  
Michele Fumagalli ◽  
Matteo Fossati ◽  
Marc Rafelski ◽  
Benjamin Oppenheimer ◽  
...  
Keyword(s):  
Absorption Line ◽  
Surface Brightness ◽  
High Redshift ◽  
Radial Profile ◽  
Clear Correlation ◽  
Star Forming ◽  
Wide Range ◽  
The Galaxy ◽  
Galaxy Environment ◽  
Galaxy Populations

ABSTRACT We present a study of the galaxy environment of nine strong H i + C iv absorption line systems (16.2 < log(N(HI)) < 21.2) spanning a wide range in metallicity at z ∼ 4−5, using MUSE integral field and X-Shooter spectroscopic data collected in a z ≈ 5.26 quasar field. We identify galaxies within a 250 kpc and ±1000 km s−1 window for six out of the nine absorption systems, with two of the absorption line systems showing multiple associated galaxies within the MUSE field of view. The space density of Ly α emitting galaxies (LAEs) around the H i and C iv systems is ≈10−20 times the average sky density of LAEs given the flux limit of our survey, showing a clear correlation between the absorption and galaxy populations. Further, we find that the strongest C iv systems in our sample are those that are most closely aligned with galaxies in velocity space, i.e. within velocities of ±500 km s−1. The two most metal-poor systems lie in the most dense galaxy environments, implying we are potentially tracing gas that is infalling for the first time into star-forming groups at high redshift. Finally, we detect an extended Ly α nebula around the z ≈ 5.26 quasar, which extends up to ≈50 kpc at the surface brightness limit of 3.8 × 10−18 erg s−1 cm−2 arcsec−2. After scaling for surface brightness dimming, we find that this nebula is centrally brighter, having a steeper radial profile than the average for nebulae studied at z ∼ 3 and is consistent with the mild redshift evolution seen from z ≈ 2.

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 < 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) > 2 × 10−17 erg s−1 cm−2) at 0.68 < z < 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) > 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 Large scale profiles of galaxies at z=0-2 studied by stacking the HSC SSP survey data

2016 ◽  
Vol 11 (S321) ◽  
pp. 318-320
Author(s):  
Mariko Kubo ◽  
Masami Ouchi ◽  
Takatoshi Shibuya
Keyword(s):  
Survey Data ◽  
Surface Brightness ◽  
Large Scale ◽  
High Redshift ◽  
Photometric Redshifts ◽  
Early Formation ◽  
The Galaxy ◽  
Strategic Program ◽  
Galaxy Populations ◽  
Using Data

AbstractWe are carrying out the study of the evolution of radial surface brightness profiles of galaxies from z = 0 to 2 by stacking analysis using data corrected by the Hyper Suprime-Cam (HSC) Subaru Strategic Program (SSP). This will allow us to constrain the large scale average profiles of various galaxy populations at high redshift. From the stacking analysis of galaxies selected based on their photometric redshifts, we successfully detected the outer components of galaxies at z > 1 extending to at least ~80 kpc, which imply an early formation for the galaxy outskirts.

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 Populations of OB-type stars in galaxies

2010 ◽  
Vol 6 (S272) ◽  
pp. 233-241
Author(s):  
Christopher J. Evans
Keyword(s):  
Stellar Evolution ◽  
Massive Stars ◽  
Spectral Synthesis ◽  
High Redshift ◽  
Young Star ◽  
Magellanic Clouds ◽  
Star Forming ◽  
The Galaxy ◽  
External Galaxies

AbstractOne of the challenges for stellar astrophysics is to reach the point at which we can undertake reliable spectral synthesis of unresolved populations in young, star-forming galaxies at high redshift. Here I summarise recent studies of massive stars in the Galaxy and Magellanic Clouds, which span a range of metallicities commensurate with those in high-redshift systems, thus providing an excellent laboratory in which to study the role of environment on stellar evolution. I also give an overview of observations of luminous supergiants in external galaxies out to a remarkable 6.7 Mpc, in which we can exploit our understanding of stellar evolution to study the chemistry and dynamics of the host systems.

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 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 Subaru High-z Exploration of Low-Luminosity Quasars (SHELLQs). VIII. A less biased view of the early co-evolution of black holes and host galaxies

2019 ◽  
Vol 71 (6) ◽  
Author(s):  
Takuma Izumi ◽  
Masafusa Onoue ◽  
Yoshiki Matsuoka ◽  
Tohru Nagao ◽  
Michael A Strauss ◽  
...  
Keyword(s):  
Black Holes ◽  
Far Infrared ◽  
Supermassive Black Holes ◽  
Host Galaxies ◽  
Star Forming ◽  
Wide Range ◽  
The Galaxy ◽  
Order Of Magnitude ◽  
Local Relation ◽  
Almost All

Abstract We present ALMA [C ii] line and far-infrared (FIR) continuum observations of three $z \gt 6$ low-luminosity quasars ($M_{\rm 1450} \gt -25$ mag) discovered by our Subaru Hyper Suprime-Cam (HSC) survey. The [C ii] line was detected in all three targets with luminosities of $(2.4\mbox{--}9.5) \times 10^8\, L_{\odot }$, about one order of magnitude smaller than optically luminous ($M_{\rm 1450} \lesssim -25$ mag) quasars. The FIR continuum luminosities range from $\lt 9 \times 10^{10}\, L_{\odot }$ (3 $\sigma$ limit) to ${\sim } 2 \times 10^{12}\, L_{\odot }$, indicating a wide range in star formation rates in these galaxies. Most of the HSC quasars studied thus far show [C ii]/ FIR luminosity ratios similar to local star-forming galaxies. Using the [C ii]-based dynamical mass ($M_{\rm dyn}$) as a surrogate for bulge stellar mass ($M_{\rm\, bulge}$), we find that a significant fraction of low-luminosity quasars are located on or even below the local $M_{\rm\, BH}$–$M_{\rm\, bulge}$ relation, particularly at the massive end of the galaxy mass distribution. In contrast, previous studies of optically luminous quasars have found that black holes are overmassive relative to the local relation. Given the low luminosities of our targets, we are exploring the nature of the early co-evolution of supermassive black holes and their hosts in a less biased way. Almost all of the quasars presented in this work are growing their black hole mass at a much higher pace at $z \sim 6$ than the parallel growth model, in which supermassive black holes and their hosts grow simultaneously to match the local $M_{\rm\, BH}$–$M_{\rm\, bulge}$ relation at all redshifts. As the low-luminosity quasars appear to realize the local co-evolutionary relation even at $z \sim 6$, they should have experienced vigorous starbursts prior to the currently observed quasar phase to catch up with the relation.

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 Morphological properties of massive galaxies at high−z from GOODS

2007 ◽  
Vol 3 (S245) ◽  
pp. 407-410 ◽  
Author(s):  
Swara Ravindranath ◽  
E. Daddi ◽  
M. Giavalisco ◽  
H. C. Ferguson ◽  
M. E. Dickinson
Keyword(s):  
Surface Brightness ◽  
Morphological Diversity ◽  
The Other ◽  
Morphological Properties ◽  
Redshift Range ◽  
Large Sample ◽  
Massive Galaxies ◽  
Star Forming ◽  
Wide Range ◽  
Deep Survey

AbstractWe have used the BzK-selection to identify a composite population of passive, and star-forming galaxies at redshifts 1.4 ≤ z ≤ 2.5 from the Great Observatories Origins Deep Survey (GOODS). Using an unprecedented large sample of galaxies in this redshift range, we characterize the morphological diversity through the analysis of the surface-brightness profile shapes for 171 galaxies with passive SEDs, and 1068 star-forming galaxies. We find that the z ~ 2 galaxies display a wide range of morphologies, from spheroidals to disk-like. Interestingly, the galaxies with passively-evolving SEDs predominantly have steep profiles as seen for the classical bulges at low redshifts, although they are very compact with re < 3 kpc. The star-forming galaxies on the other hand exhibit mostly disk-like and merger morphologies, and have sizes comparable to their low−z counterparts. Our results emphasize the need for an unbiased selection in order to reveal the morphological diversities, and range of galaxy properties at high redshifts.

scholarly journals Jansky VLA S-band view of Hα emitters (HAEs) associated with a protocluster 4C23.56 at z = 2.5

2014 ◽  
Vol 10 (S309) ◽  
pp. 287-288
Author(s):  
Minju Lee ◽  
Kenta Suzuki ◽  
Kotaro Kohno ◽  
Yoichi Tamura ◽  
Daisuke Iono ◽  
...  
Keyword(s):  
Galaxy Formation ◽  
Narrow Band ◽  
Narrow Band Imaging ◽  
Large Array ◽  
Dense Region ◽  
Very Large Array ◽  
Star Forming ◽  
Dust Extinction ◽  
The Galaxy ◽  
Galaxy Populations

AbstractWe present recent results on Karl Jansky Very Large Array (JVLA) deep S-band (2-4 GHz) observation towards a protocluster 4C23.56 at redshift z ∼ 2.5. The protocluster 4C23.56 is known to have a significant over density (∼ 5 times) of star-burst galaxies selected to be Hα line-bright by a Subaru narrow band imaging. Now we have found 25 HAEs associated with the protocluster. These starburst HAEs are likely to become massive ellipticals at z = 0 in a cluster. Various other galaxy populations also reside in this field and the fact makes the field very unique as a tool to understand galaxy formation in a over dense region. Subsequent deep 1100-μm continuum surveys by the ASTE 10-m dish have discovered that several submillimeter bright galaxies (SMGs) coincide with HAEs, suggesting HAEs undergoing dusty starbursts. As star formation rates (SFRs) of HAEs might have been underestimated, we use radio being resistant to dust extinction. We investigate the correlation between SFR1.4 GHz and SFRHα for radio index α = 0.8 to see if the correlation holds for the sources and to check the number of dusty star forming galaxies. Our final results will allow us to evaluate quantitatively how the galaxy formation channel may be different under the condition of over-densities.

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