This paper presents a detailed analysis of two giant Lyman-alpha (Lya) arcs detected near known galaxies at z=3.038 and z=3.754 lensed by the massive cluster MACS 1206 (z=0.44). The Lya nebulae revealed in deep MUSE observations exhibit a double-peak profile with a dominant red peak that indicates expansion/outflowing motions. One of the arcs stretches over 1' around the Einstein radius of the cluster, resolving the velocity field of the line-emitting gas on kpc scales around a group of three star-forming galaxies of 0.3-1.6L* at z=3.038. The second arc spans 15'' in size, roughly centered around a pair of low-mass Lya emitters of ~0.03L* at z=3.754. All three galaxies in the z=3.038 group exhibit prominent damped Lya absorption (DLA) and several metal absorption lines, in addition to nebular emission lines such as HeII1640 and CIII]1906,1908. Extended Lya emission appears to emerge from star-forming regions to larger distances with suppressed surface brightness at the center of each galaxy, suggesting the presence of dusty outflowing cones of size 1-5 kpc across. There are significant spatial variations in the Lya line profile, consistent with the presence of a steep negative velocity gradient in a continuous flow of high column density gas from star-forming regions into a low-density halo environment. While the observed UV nebular line ratios show no evidence of AGN activity in the galaxies, the observed Lya signals can be explained by a combination of resonant scattering and recombination radiation due to photoionization by ionizing photons escaping from the nearby star-forming regions. These observations provide the most detailed insights yet into the kinematics of galactic superwinds associated with star-forming galaxies thought to be responsible for the chemical enrichment in the intergalactic medium.
During five decades astronomers have been puzzled by the presence of strong absorption features including metal lines, observed in the optical and ultraviolet spectra of quasars, signalling in- and outflowing gas winds with relative velocities up to several thousands of km/sec. In particular the location of these winds - close to the quasar, further out in its host galaxy, or in its direct environment - and the possible impact on their surroundings have been issues of intense discussion and uncertainty. Using our Herschel Space Observatory data, we report a tendency for this so-called associat…
One of the main challenges in using high redshift active galactic nuclei to study the correlations between the mass of the supermassive Black Hole (MBH) and the properties of their active host galaxies is instrumental resolution. Strong lensing magnification effectively increases instrumental resolution and thus helps to address this challenge. In this work, we study eight strongly lensed active galactic nuclei (AGN) with deep Hubble Space Telescope imaging, using the lens modelling code Lenstronomy to reconstruct the image of the source. Using the reconstructed brightness of the host galaxy, …
Galactic winds are associated with intense star formation and AGNs. Depending on their formation mechanism and velocity they may remove a significant fraction of gas from their host galaxies, thus suppressing star formation, enriching the intergalactic medium, and shaping the circumgalactic gas. However, the long-term evolution of these winds remains mostly unknown. We report the detection of a wind from NGC 3079 to at least 60 kpc from the galaxy. We detect the wind in FUV line emission to 60 kpc (as inferred from the broad FUV filter in GALEX) and in X-rays to at least 30~kpc. The morphology…
Discovery of a radio jet in the Cloverleaf Quasar at z = 2.56
Nanjing University（南京大学）；Key Laboratory of Modern Astronomy and Astrophysics (Nanjing University), Ministry of Education（现代天文学与天体物理学教育部重点实验室（南京大学））；Department of Physics, Institute for Computational Cosmology, Durham University（杜伦大学计算宇宙学研究所物理系）；National Astronomical Observatories, Chinese Academy of Sciences（中国科学院国家天文台）；Department of Space, Earth and Environment, Chalmers University of Technology（查尔姆斯理工大学空间、地球与环境学院）；European Southern Observatory（欧洲南方天文台）
To understand the origin of radio emission in radio-quiet AGN and differentiate between the contributions from star formation, AGN accretion, and jets, we have observed a nearby sample of Seyfert galaxies along with a comparison sample of starburst galaxies using the EVLA in full-polarization mode in the B-array configuration. The radio morphologies of the Seyfert galaxies show lobe/bubble-like features or prominent cores in radio emission whereas the starburst galaxies show radio emission spatially coincident with the star-forming regions seen in optical images. There is tentative evidence th…
We present the reconstructed evolution of rest-frame ultra-violet (UV) luminosities of the most massive Milky Way dwarf spheroidal satellite galaxy, Fornax, and its five globular clusters (GCs) across redshift, based on analysis of the stellar fossil record and stellar population synthesis modeling. We find that (1) Fornax's (proto-)GCs can generate $10-100$ times more UV flux than the field population, despite comprising $<\sim 5\%$ of the stellar mass at the relevant redshifts; (2) due to their respective surface brightnesses, it is more likely that faint, compact sources in the Hubble Front…
Globular clusters (GCs) formed when the Milky Way experienced a phase of rapid assembly. We use the wealth of information contained in the Galactic GC population to quantify the properties of the satellite galaxies from which the Milky Way assembled. To achieve this, we train an artificial neural network on the E-MOSAICS cosmological simulations of the co-formation and co-evolution of GCs and their host galaxies. The network uses the ages, metallicities, and orbital properties of GCs that formed in the same progenitor galaxies to predict the stellar masses and accretion redshifts of these prog…
In Paper I (Safarzadeh & Berger 2019) we studied the determination of the delay time distribution (DTD) of binary neutron stars (BNS) through scaling relations between halo/stellar mass and the star formation history (SFH) of galaxies hosting gravitational wave (GW) events in the local universe. Here we explore how a detailed reconstruction of the individual SFHs of BNS merger host galaxies can improve on the use of the scaling relations. We use galaxies from the Galaxy and Mass Assembly (GAMA) survey, which is mass complete at $M_*>10^9$ M$_\odot$ in the redshift range $0.05<z<0.08$. We use t…
Galactic superwinds may be driven by very hot outflows generated by overlapping supernovae within the host galaxy. We use the Chevalier & Clegg (CC85) wind model and the observed correlation between X-ray luminosities of galaxies and their SFRs to constrain the mass loss rates (\dot{M}_hot) across a wide range of star formation rates (SFRs), from dwarf starbursts to ultra-luminous infrared galaxies. We show that for fixed thermalization efficiency and mass loading rate, the X-ray luminosity of the hot wind scales as L_X ~ SFR^2, significantly steeper than is observed for star-forming galaxies:…
We present ALMA 2-mm continuum and CO (2-1) spectral line imaging of the gravitationally lensed z=0.654 star-forming/quasar composite RX J1131-1231 at 240-400 mas angular resolution. The continuum emission is found to be compact and coincident with the optical emission, whereas the molecular gas forms a complete Einstein ring, which shows strong differential magnification. The de-lensed source structure is determined on 400-pc resolution using a visibility-fitting lens modelling technique. The reconstructed molecular gas velocity-field is consistent with a rotating disk with a maximum rotation…
The duration of a starburst is a fundamental parameter affecting the evolution of galaxies yet, to date, observational constraints on the durations of starbursts are not well established. Here we study the recent star formation histories (SFHs) of three nearby dwarf galaxies to rigorously quantify the duration of their starburst events using a uniform and consistent approach. We find that the bursts range from ~200 - ~400 Myr in duration resolving the tension between the shorter timescales often derived observationally with the longer timescales derived from dynamical arguments. If these three…
Group Pre-processing in J1611+4026: Minor Rejuvenation of a Massive ETG fueled by Interaction-driven Gas Transfer
South-Western Institute for Astronomy Research, Yunnan University（西南天文研究所，云南大学）；School of Physics and Astronomy, Beijing Normal University（北京师范大学物理与天文学院）；Institute for Frontier in Astronomy and Astrophysics, Beijing Normal University（北京师范大学前沿天文与天体物理研究所）；Department of Physics, Nanchang University（南昌大学物理系）；Center for Relativistic Astrophysics and High Energy Physics, Nanchang University（南昌大学相对论天体物理与高能物理中心）；Purple Mountain Observatory, Chinese Academy of Sciences（中国科学院紫金山天文台）；Technical University of Munich, TUM School of Natural Sciences, Physics Department（慕尼黑工业大学自然科学学院物理系）；Max Planck Institute for Astrophysics（马克斯·普朗克天体物理学研究所）
A New PSF Deconvolution Algorithm: Simultaneous Spatial Resolution Enhancement and Point Source Removal for Morphological Analysis of AGN Host Galaxies
We present the mean spectral energy distribution (SED) of a sample of optically selected quasars (QSOs) at redshifts of $1 \le z \le 5$. To derive it, we exploit photometric information from SDSS, UKIDSS, and WISE surveys in combination with a stacking analysis of \textit{Herschel}, \textit{AKARI}, and \textit{Planck} maps at the location of the QSOs. The near-UV and optical parts of the reconstructed mean rest-frame SED are similar to those found in other studies. However, the SED shows an excess at 1-2 $μ$m (when compared to the aforementioned SEDs normalized in the near-UV) and a prominent …
Black hole masses are found to correlate with several global properties of their host galaxies, suggesting that black holes and galaxies have an intertwined evolution and that active galactic nuclei (AGN) have a significant impact on galaxy evolution. Since the large-scale environment can also affect AGN, this work studies how their formation and properties depend on the environment. We have used a reconstructed three-dimensional high-resolution density field obtained from a Bayesian large-scale structure reconstruction method applied to the 2M++ galaxy sample. A web-type classification relyin…
Environmental Dependence of Satellite Planarity and Orbital-Pole Coherence around Milky Way Analogues in a Hydrodynamical Cosmological Simulation
Shanghai Astronomical Observatory, Chinese Academy of Sciences（中国科学院上海天文台）；Department of Physics, School of Physics and Electronics, Hunan Normal University（湖南师范大学物理科学与电子学院）；Purple Mountain Observatory, Chinese Academy of Sciences（中国科学院紫金山天文台）；Institute of Astronomy, School of physics, Zhejiang University（浙江大学物理学院天体物理研究所）；Institute of Astronomy and Physics, Inner Mongolia University（内蒙古大学天文与物理学院）；National Astronomical Observatories, Chinese Academy of Sciences（中国科学院国家天文台）
We present a detailed study of the metal-enriched circum-galactic medium of a massive galaxy at z=3 using "ErisMC", a new cosmological hydrodynamic "zoom-in" simulations of a disk galaxy with mass comparable to the Milky Way. The run adopts a blastwave scheme for supernova feedback that generates galactic outflows without explicit wind particles, a star formation recipe based on a high gas density threshold, and high temperature metal cooling. ErisMC's main progenitor at z=3 resembles a "Lyman break" galaxy of mass M_vir=2.4e11 M_sun, virial radius R_vir=48 kpc, and star formation rate 18 M_su…
We analyse the correlations between continuum properties and emission line equivalent widths of star-forming and active galaxies from the Sloan Digital Sky Survey. Since upcoming large sky surveys will make broad-band observations only, including strong emission lines into theoretical modelling of spectra will be essential to estimate physical properties of photometric galaxies. We show that emission line equivalent widths can be fairly well reconstructed from the stellar continuum using local multiple linear regression in the continuum principal component analysis (PCA) space. Line reconstruc…
