Proceeding of "Heidelberg International Symposium on High Energy Gamma-Ray Astronomy", held in Heidelberg, 7-11 July 2008, submitted to AIP Conference Proceedings. 4 pages, 4 figures
The survey of the inner Galaxy with H.E.S.S. was remarkably successful in detecting a wide range of new very-high-energy gamma-ray sources. New TeV gamma-ray emitting source classes were established, although several of the sources remain unidentified, and progress has been made in understanding particle acceleration in astrophysical sources. In this work, we constructed a model of a population of such very-high-energy gamma-ray emitters and normalised the flux and size distribution of this population model to the H.E.S.S.-discovered sources. Extrapolating that population of objects to lower flux levels we investigate what a future array of imaging atmospheric telescopes (IACTs) such as AGIS or CTA might detect in a survey of the Inner Galaxy with an order of magnitude improvement in sensitivity. The sheer number of sources detected together with the improved resolving power will likely result in a huge improvement in our understanding of the populations of galactic gamma-ray sources. A deep survey of the inner Milky Way would also support studies of the interstellar diffuse gamma-ray emission in regions of high cosmic-ray density. In the final section of this paper we investigate the science potential for the Galactic Centre region for studying energy-dependent diffusion with such a future array.
Collisions and interactions between gas-rich galaxies are thought to be pivotal stages in their formation and evolution, causing the rapid production of new stars, and possibly serving as a mechanism for fueling supermassive black holes (BH). Harnessing the exquisite spatial resolution (~0.5 arcsec) afforded by the first ~170 deg^2 of the Hyper Suprime-Cam (HSC) Survey, we present our new constraints on the importance of galaxy-galaxy major mergers (1:4) in growing BHs throughout the last ~8 Gyrs. Utilizing mid-infrared observations in the WISE All-Sky survey, we robustly select active galacti…
We present here a brief summary of the currenly on-going IFU surveys of galaxies in the Local Universe, describing their main characteristics, including their sample selections, instrumental setups, wavelength ranges, and area of the galaxies covered. Finally, we make an emphasis on the main characteristics of the CALIFA survey and the more recent results that has been recently published
Planck data towards the galaxy M82 are analyzed in the 70, 100 and 143 GHz bands. A substantial north-south and East-West temperature asymmetry is found, extending up to 1 degree from the galactic center. Being almost frequency-independent, these temperature asymmetries are indicative of a Doppler-induced effect regarding the line-of-sight dynamics on the halo scale, the ejections from the galactic center and, possibly, even the tidal interaction with M81 galaxy. The temperature asymmetry thus acts as a model-independent tool to reveal the bulk dynamics in nearby edge-on spiral galaxies, like …
We have mapped cold atomic gas in 21cm line HI self-absorption (HISA) at arcminute resolution over more than 90% of the Milky Way's disk. To probe the formation of H2 clouds, we have compared our HISA distribution with CO J=1-0 line emission. Few HISA features in the outer Galaxy have CO at the same position and velocity, while most inner-Galaxy HISA has overlapping CO. But many apparent inner-Galaxy HISA-CO associations can be explained as chance superpositions, so most inner-Galaxy HISA may also be CO-free. Since standard equilibrium cloud models cannot explain the very cold HI in many HISA …
Understanding how galaxies form in the early universe and their subsequent evolution through cosmic time is a major goal of modern astrophysics. Panchromatic look-back sky surveys significantly advanced the field in the past decades, and we are now entering an even more fruitful period - a 'golden age' of radio astronomy - with upgraded, and new facilities delivering an order of magnitude increase in sensitivity. An overview of recent developments in radio continuum sky surveys, focusing on the physical properties and cosmic evolution of radio AGN since z~5 is presented here.
Our neighbouring large spiral galaxy, the Andromeda galaxy (M 31 or NGC 224), is an ideal target to study the X-ray source population of a nearby galaxy. NuSTAR observed the central region of M 31 in 2015 and allows studying the population of X-ray point sources at energies higher than 10 keV. Based on the source catalogue of the large XMM-Newton survey of M 31, we identified counterparts to the XMM-Newton sources in the NuSTAR data. The NuSTAR data only contain sources of a brightness comparable (or even brighter) than the selected sources that have been detected in XMM-Newton data. We invest…
We present supporting evidence for the first association of a Fermi source, 3FGLJ1330.0-3818, with the FR0 radio galaxy Tol1326-379. FR0s represent the majority of the local radio loud AGN population but their nature is still unclear. They share the same properties of FRIs from the point of view of the nuclear and host properties, but they show a large deficit of extended radio emission. Here we show that FR0s can emit photons at very high energies. Tol1326-379 has a GeV luminosity of $L_{>1~{\rm GeV}} \sim 2\times10^{42}$ erg s$^{-1}$, typical of FRIs, but with a steeper $γ$-ray spectrum ($Γ=…
We present new spectra obtained using Keck/KCWI and perform kinematics and stellar population analyses of the shell galaxy NGC 474, from both the galaxy centre and a region from the outer shell. We show that both regions have similarly extended star formation histories although with different stellar population properties. The central region of NGC 474 is dominated by intermediate-aged stars (8.3 \pm 0.3 Gyr) with subsolar metallicity ([Z/H]= -0.24 \pm 0.07 dex) while the observed shell region, which hosts a substantial population of younger stars, has a mean luminosity-weighted age of 4.0 \pm…
Galaxy groups constitute the most common class of galaxy systems in the known Universe, unique in terms of environmental properties. However, despite recent advances in optical and infrared observations as well as in theoretical research, little is known about magnetic fields and the associated continuum radio emission. Studies on this issue have only been conducted in recent years, and many questions have yet to be resolved. This article aims to put the study of group magnetism in a broader context, to present recent advances in the field (mainly achieved with low-frequency radio interferomet…
We present here a brief summary of the status of the on-going CALIFA survey. We have just started the last semester of observing (Spring 2015). So far, we have gathered IFU data of more than 600 galaxies, ~85% of them corresponding to the main CALIFA sample (516 objects). We give an overview of some of the main science results that have been published by the CALIFA team during the last four years. In particular, we emphasise the results regarding the properties of the ionized gas in galaxies and the gradients in oxygen abundance, as well as the evidence for inside-out growth of galaxies uncove…
We report on the discovery and chemical abundance analysis of the first CEMP-r/s star detected in the Sagittarius dwarf Spheroidal Galaxy, by means of UVES high resolution spectra. The star, found in the outskirts of Sgr dSph, along the main body major axis, is a moderately metal poor giant (T$_{eff}$=4753 K, log g=1.75, [Fe/H]=-1.55), with [C/Fe]=1.13 placing it in the so-called "high-carbon band", and strong s-process and r-process enrichment ([Ba/Fe]=1.4, [Eu/Fe]=1.01). Abundances of 29 elements from C to Dy were obtained. The chemical pattern appears to be best fitted by a scenario where a…
Radio observations over the last two decades have provided evidence that diffuse synchrotron emission in the form of megaparsec-scale radio halos in galaxy clusters is likely tracing regions of the intracluster medium where relativistic particles are accelerated during cluster mergers. In this paper we present results of a survey of 14 galaxy clusters carried out with the 7-element Karoo Array Telescope at 1.86 GHz, aimed to extend the current studies of radio halo occurrence to systems with lower masses (M$_{\rm 500} > 4\times10^{14}$ M${_\odot}$). We found upper limits at the $0.6 - 1.9 \tim…
We report the discovery of a massive $\log(M/M_\odot)=10.74^{+0.18}_{-0.16}$ galaxy at the same redshift as a carbon-monoxide-bearing sub-damped Lyman $α$ absorber (sub-DLA) seen in the spectrum of QSO J1439+1117. The galaxy, J1439B, is located 4\farcs7 from the QSO sightline, a projected distance of 38 physical kpc at $z=2.4189$, and exhibits broad optical emission lines ($σ_{\rm{[O III]}}=303 \pm 12$~\kms) with ratios characteristic of excitation by an active galactic nucleus (AGN). The galaxy has a factor of $\sim$9 lower star formation than is typical of star-forming galaxies of the same m…
We used FORS2 in MXU mode to mimic a coarse 'IFU' in order to measure the 3D large-scale kinematics around the central Hydra I cluster galaxy NGC 3311. Our data show that the velocity dispersion field varies as a function of radius and azimuthal angle and violates point symmetry. Also, the velocity field shows similar dependence, hence the stellar halo of NGC 3311 is a dynamically young structure. The kinematic irregularities coincide in position with a displaced diffuse halo North-East of NGC 3311 and with tidal features of a group of disrupting dwarf galaxies. This suggests that the superpos…
The low distance, $z=0.0591$, of GRB 100316D and its association with SN 2010bh represent two important motivations for studying this host galaxy and the GRB's immediate environment with the Integral-Field Spectrographs like VLT/MUSE. Its large field-of-view allows us to create 2D maps of gas metallicity, ionization level, and the star-formation rate distribution maps, as well as to investigate the presence of possible host companions. The host is a late-type dwarf irregular galaxy with multiple star-forming regions and an extended central region with signatures of on-going shock interactions.…
Supermassive black hole binaries (SMBHBs) are productions of the hierarchical galaxy formation model. There are many close connections between central SMBH and its host galaxy because the former plays very important roles on the formation and evolution of a galaxy. For this reason, the evolution of SMBHBs in merging galaxies is an essential problem. Since there are many discussions about SMBHB evolution in gas rich environment, we focus on the quiescent galaxy, using tidal disruption as a diagnostic tool. Our study is based on a series of numerical large particle number direct N-body simulatio…
Recent panoramic observations of the dominant spiral galaxies of the Local Group have revolutionized our view of how these galaxies assemble their mass. However, it remains completely unclear whether the properties of the outer regions of the Local Group large spirals are typical. Here, we present the first panoramic view of a spiral galaxy beyond the Local Group, based on the largest, contiguous, ground-based imaging survey to date resolving the stellar halo of the nearest prime analogue of the Milky Way, NGC 891 (D~10 Mpc). The low surface brightness outskirts of this galaxy are populated by…
Dwarf galaxies make ideal laboratories to test galaxy evolution paradigms and cosmological models. Detailed studies of dwarfs across the spectrum allow us to gauge the efficacy of astrophysical processes at play in the lowest mass halos such as gas accretion, feedback, turbulence and chemical enrichment. Future observational studies will deliver unprecedented insights on the orbits of dwarf companions around the Milky Way, on their star formation histories and on the 3-D internal motions of their stars. Over large volumes, we will assess the impact of local environment on baryon cycling and st…
Future prospects in observational galaxy evolution are reviewed from a personal perspective. New insights will especially come from high-redshift integral field kinematic data and similar low-redshift observations in very large and definitive surveys. We will start to systematically probe the mass structures of galaxies and their haloes via lensing from new imaging surveys and upcoming near-IR spectroscopic surveys will finally obtain large numbers of rest frame optical spectra at high-redshift routinely. ALMA will be an important new ingredient, spatially resolving the molecular gas fuelling …
Double bars are thought to be important features for secular evolution in the central regions of galaxies. However, observational evidence about their origin and evolution is still scarce. We report on the discovery of the first Box-Peanut (B/P) structure in an inner bar detected in the face-on galaxy NGC 1291. We use the integral field data obtained from the MUSE spectrograph within the TIMER project. The B/P structure is detected as bi-symmetric minima of the $h_4$ moment of the line-of-sight velocity distribution along the major axis of the inner bar, as expected from numerical simulations.…
NGC 891 is a nearby edge-on galaxy that is similar to the Milky Way and has a hot X-ray emitting halo that could arise from accretion, a galactic fountain, or a combination of the two. The metallicity of the gas can help distinguish between these models, and here we report on results that use 138 ks of archival Chandra data and 92 ks of new XMM-Newton data to measure the temperature and metallicity of the hot halo of the galaxy. We find good fits for a thermal model with kT ~ 0.2 keV and Z ~ 0.1 solar, and rule out solar metallicity to more than 99% confidence. This result suggests accretion f…
We present a study of the physical properties of JO201, a unique disk galaxy with extended tails undergoing extreme ram-pressure stripping as it moves through the massive cluster Abell 85 at supersonic speeds mostly along the line of sight. JO201 was observed with MUSE as part of the GASP programme. In a previous paper (GASP II) we studied the stellar and gas kinematics. In this paper we present emission-line ratios, gas-phase metallicities and ages of the stellar populations across the galaxy disk and tails. We find that while the emission at the core of the galaxy is dominated by an active g…
We review progress in the development of physically realistic three dimensional simulated models of the galaxy.We consider the scales from star forming molecular clouds to the full spiral disc. Models are computed using hydrodynamic (HD) or magnetohydrodynamic (MHD) equations and may include cosmic ray or tracer particles. The range of dynamical scales between the full galaxy structure and the turbulent scales of supernova (SN) explosions and even cloud collapse to form stars, make it impossible with current computing tools and resources to resolve all of these in one model. We therefore consi…
Context: The Ophiuchus cluster of galaxies, located at low latitudes in the direction of the Galactic bulge, has been relatively poorly studied in comparison with other rich galaxy clusters like Coma, Virgo and Fornax, in spite of being the 2nd brightest X-ray cluster in the sky. Methods: Deep near-infrared images and photometry from the VISTA Variables in the Vía Láctea eXtended survey (VVVX) were used to detect galaxy member candidates of Ophiuchus cluster up to 2 Mpc from the cD galaxy 2MASX J17122774-2322108 using the Galdeano et al. criteria to select the galaxies among the foreground sou…
The gap between first and second ranked galaxy magnitudes in groups is often considered a tracer of their merger histories, which in turn may affect galaxy properties, and also serves to test galaxy luminosity functions (LFs). We remeasure the conditional luminosity function (CLF) of the Main Galaxy Sample of the SDSS in an appropriately cleaned subsample of groups from the Yang catalog. We find that, at low group masses, our best-fit CLF have steeper satellite high ends, yet higher ratios of characteristic satellite to central luminosities in comparison with the CLF of Yang et al. (2008). The…
In this work, we studied ten nearby ($z$$ \leq$0.038) galaxy clusters to understand possible interactions between hot plasma and member galaxies. A multi-band source detection was applied to detect point-like structures within the intra-cluster medium. We examined spectral properties of a total of 391 X-ray point sources within cluster's potential well. Log $N$ - Log $S$ was studied in the energy range of 2-10 keV to measure X-ray overdensities. Optical overdensities were also calculated to solve suppression/triggering phenomena for nearby galaxy clusters. Both X-ray to optical flux/luminosity…
In the context of the GAs Stripping Phenomena in galaxies with Muse (GASP) survey, we present the characterization of JO204, a jellyfish galaxy in A957, a relatively low-mass cluster with $M=4.4 \times10^{14}M_\odot$. This galaxy shows a tail of ionized gas that extends up to 30 kpc from the main body in the opposite direction of the cluster center. No gas emission is detected in the galaxy outer disk, suggesting that gas stripping is proceeding outside-in. The stellar component is distributed as a regular disk galaxy; the stellar kinematics shows a symmetric rotation curve with a maximum radi…
Galaxies in dense environments, such as groups and clusters, experience various processes by which galaxies gain and lose gas. Using data from the SDSS-IV MaNGA survey, we previously reported the discovery of a giant (6 -- 8 kpc in diameter) H$α$ blob, Totoro, about 8 kpc away from a pair of galaxies (Satsuki and Mei) residing in a galaxy group which is experiencing a group-group merger. Here, we combine interferometric $^{12}$CO(1--0) molecular gas data, new wide-field H$α$, $u$-band data, and published X-ray data to determine the origin of the blob. Several scenarios are discussed to account…
We explore the co-evolution of galaxies in nearby groups (V < 3000 km/s) with a multi-wavelength approach. We analyze GALEX far-UV (FUV) and near-UV (NUV) imaging and SDSS u,g,r,i,z data of groups spanning a large range of dynamical phases. We characterize the photometric properties of spectroscopically-confirmed galaxy members and investigate the global properties of the groups through a dynamical analysis. Here we focus on NGC 5846, the third most massive association of Early-Type Galaxies (ETG) after the Virgo and Fornax clusters. The group, composed of 90 members, is dominated by ETGs (abo…
Jellyfish are cluster galaxies that experience strong ram-pressure effects that strip their gas. Their H$α$ images reveal ionized gas tails up to 100 kpc, which could be hosting ongoing star formation. Here we report the ultraviolet (UV) imaging observation of the jellyfish galaxy JO201 obtained at a spatial resolution $\sim$ 1.3 kpc. The intense burst of star formation happening in the tentacles is the focus of the present study. JO201 is the "UV-brightest cluster galaxy" in Abell 85 ($z \sim$ 0.056) with knots and streams of star formation in the ultraviolet. We identify star forming knots b…
We investigate the dust-obscured star formation properties of the massive, X-ray selected galaxy cluster MACS J1931.8-2634 at $z$=0.352. Using far-infrared (FIR) imaging in the range 100-500$μ$m obtained with the \textit{Herschel} telescope, we extract 31 sources (2$σ$) within $r\sim$1 Mpc from the brightest cluster galaxy (BCG). Among these sources we identify six cluster members for which we perform an analysis of their spectral energy distributions (SEDs). We measure total infrared luminosity (L$_{IR}$), star formation rate (SFR) and dust temperature. The BCG, with L$_{IR}$=1.4$\times$10$^{…
MOSS III: MeerKATs view on the galaxy populations in two massive galaxy clusters
Institute of Physics, École Polytechnique Fédérale de Lausanne (EPFL)（洛桑联邦理工学院物理研究所）；Astronomical Observatory Institute, Faculty of Physics, Adam Mickiewicz University（亚当·密茨凯维奇大学物理学院天文台研究所）；National Radio Astronomy Observatory (NRAO)（美国国家射电天文台）；Tartu Observatory, University of Tartu（塔尔图大学塔尔图天文台）；National Centre for Radio Astrophysics, Tata Institute of Fundamental Research（塔塔基础研究院国家射电天体物理学中心）
We present an analysis of the kinematics and ionization conditions in a sample composed of seven star-forming galaxies undergoing ram-pressure stripping in the A1367 cluster, and the galaxy ESO137-001 in the Norma cluster. MUSE observations of two new galaxies in this sample, CGCG097-073 and CGCG097-079, are also presented. This sample is characterized by homogeneous integral field spectroscopy with MUSE and by a consistent selection based on the presence of ionised gas tails. The ratio [OI]/H$α$ is consistently elevated in the tails of these objects compared to what observed in unperturbed ga…
We present a panoramic survey of the isolated Local Group dwarf irregular galaxy NGC 6822. Our photometry reaches $\sim2-3$ magnitudes deeper than most previous studies and spans the widest area around the dwarf compared to any prior work. We observe no stellar over-densities in the outskirts of NGC 6822 to $V\sim 30$ mag$\,$arcsec$^{-2}$ and a projected radius of $16.5$ kpc. This indicates that NGC 6822 has not experienced any recent interaction with a companion galaxy, despite previous suggestions to the contrary. Similarly, we find no evidence for any dwarf satellites of NGC 6822 to a limit…
Modern observational and analytic techniques now enable the direct measurement of star formation histories and the inference of galaxy assembly histories. However, current theoretical predictions of assembly are not ideally suited for direct comparison with such observational data. We therefore extend the work of prior examinations of the contribution of ex-situ stars to the stellar mass budget of simulated galaxies. Our predictions are specifically tailored for direct testing with a new generation of observational techniques by calculating ex-situ fractions as functions of galaxy mass and mor…
Much of our current understanding of neutral, atomic gas in galaxies comes from radio observations of the nearby Universe. Until the next generation of instruments allow us to push to much higher redshifts, we must rely mostly upon theoretical models of galaxy formation to provide us with key insights into the likely cosmic evolution of HI in the Universe, and its links to molecular clouds and star formation. In this work, we present a new set of methods to convert mock galaxy catalogues into synthetic data cubes containing model galaxies with realistic spatial and spectral HI distributions ov…
X-ray selected samples are known to miss galaxy clusters that are gas poor and have a low surface brightness. This is different for the optically selected samples such as the X-ray Unbiased Selected Sample (XUCS). We characterise the origin of galaxy clusters that are gas poor and have a low surface-brightness by studying covariances between various cluster properties at fixed mass using hydrodynamic cosmological simulations. We extracted approx. 1800 galaxy clusters from a high-resolution Magneticum hydrodynamic cosmological simulation and computed covariances at fixed mass of the following p…
We determine the detection limits of the search for dwarf galaxies in the Pan-Andromeda Archaeological Survey (PAndAS) using the algorithm developed by the PAndAS team. The recovery fractions of artificial dwarf galaxies are, as expected, a strong function of physical size and luminosity and, to a lesser extent, distance. We show that these recovery fractions vary strongly with location in the surveyed area because of varying levels of contamination from both the Milky Way foreground stars and the stellar halo of Andromeda. We therefore provide recovery fractions that are a function of size, l…
Star forming dwarf galaxies in the local volume are diverse and are ideal test beds to understand details of star formation in a variety of environments. Here, we present a deep FUV imaging study of a nearby dwarf irregular galaxy IC 2574 using the Ultraviolet Imaging Telescope (UVIT). We identified 419 FUV bright regions with radii between 15 - 285 pc in the galaxy and found that 28.6\% of them to be located in H~I shells, 12.6\% inside holes and 60.1\% to be away from the holes. The H~I column density is found to be more than $10^{21} cm^{-2}$ for 82.3\% of the identified regions. 30 out of …
Galaxy mergers are known to host abundant young massive cluster (YMC) populations, whose formation mechanism is still not well-understood. Here, we present a high-resolution galaxy merger simulation with explicit star formation and stellar feedback prescriptions to investigate how mergers affect the properties of the interstellar medium and YMCs. Compared with a controlled simulation of an isolated galaxy, the mass fraction of dense and high-pressure gas is much higher in mergers. Consequently, the mass function of both molecular clouds and YMCs becomes shallower and extends to higher masses. …
The nature of our Milky Way Galaxy is reexamined from an eclectic point of view. Evidence for a central bar, for example, is not reflected in the distribution of RR Lyrae variables in the central bulge [4,5], and it is not clear if either a 2-armed or 4-armed spiral pattern is appropriate for the spiral arms. Radial velocity mapping of the Galaxy using radio H I, H II, or CO observations is compromised by the assumptions adopted for simple Galactic rotation. The Sun's local standard of rest (LSR) velocity is $\sim 14$ km s$^{-1}$ rather than 20 km s$^{-1}$, the local circular velocity is $251 …
The role of active galactic nuclei (AGNs) during galaxy interactions and how they influence the star formation in the system are still under debate. We use a sample of 1156 galaxies in galaxy pairs or mergers (hereafter `pairs') from the MaNGA survey. This pair sample is selected by the velocity offset, projected separation, and morphology, and is further classified into four cases along the merger sequence based on morphological signatures. We then identify a total of 61 (5.5%) AGNs in pairs based on the emission-line diagnostics. No evolution of the AGN fraction is found, either along the me…
Introducing the Condor Array Telescope. II. Deep imaging observations of the edge-on spiral galaxy NGC 5907 and the NGC 5866 Group: yet another view of the iconic stellar stream
Using data taken as part of the Bluedisk project we study the connection between neutral hydrogen (HI) in the environment of spiral galaxies and that in the galaxies themselves. We measure the total HI mass present in the environment in a statistical way by studying the distribution of noise peaks in the HI data cubes obtained for 40 galaxies observed with WSRT. We find that galaxies whose HI mass fraction is high relative to standard scaling relations have an excess HI mass in the surrounding environment as well. Gas in the environment consists of gas clumps which are individually below the d…
Two major questions in galaxy evolution are how star-formation on small scales leads to global scaling laws and how galaxies acquire sufficient gas to sustain their star formation rates. HI observations with high angular resolution and with sensitivity to very low column densities are some of the important observational ingredients that are currently still missing. Answers to these questions are necessary for a correct interpretation of observations of galaxy evolution in the high-redshift universe and will provide crucial input for the sub-grid physics in hydrodynamical simulations of galaxy …
Stellar shells are low surface brightness features, created during nearly head-on galaxy mergers from the debris of the tidally disrupted satellite. Here, we investigate the formation and evolution mechanism of shells in six dimensions (3d positions and velocities). We propose a new description in action-angle coordinates which condenses the seemingly complex behaviour of an expanding shell system into a simple picture, and stresses the crucial role of the existence of different stripping episodes in the properties of shells. Based on our findings, we construct a method for constraining the po…
We present far-infrared (FIR) properties of an extremely luminous infrared galaxy (ELIRG) at $z_{\rm spec}$ = 3.703, WISE J101326.25+611220.1 (WISE1013+6112). This ELIRG is selected as an IR-bright dust-obscured galaxy (DOG) based on the photometry from the Sloan digital sky survey (SDSS) and wide-field infrared survey explorer (WISE). In order to derive its accurate IR luminosity, we perform follow-up observations at 89 and 154 $μ$m using the high-resolution airborne wideband camera-plus (HAWC+) on board the 2.7-m stratospheric observatory for infrared astronomy (SOFIA) telescope. We conduct …
The kinematics and stellar populations of the low-mass nearby S0 galaxy NGC 5102 are studied from integral field spectra taken with the Multi-Unit Spectroscopic Explorer (MUSE). The kinematic maps reveal for the first time that NGC 5102 has the characteristic 2 sigma peaks indicative of galaxies with counter-rotating discs. This interpretation is quantitatively confirmed by fitting two kinematic components to the observed spectra. Through stellar population analysis we confirm the known young stellar population in the centre and find steep age and metallicity gradients. We construct axisymmetr…
We report deep optical integral-field spectroscopy with the MUSE of the luminous radio-quiet QSO PG1307+085 (z=0.154) obtained during the commissioning of the instrument. Given the high sensitivity and spatial resolution delivered by MUSE, we are able to resolve the compact ($r_e$~1.3") elliptical host galaxy. After careful spectroscopic deblending of the QSO and host galaxy emission, we infer a stellar velocity dispersion of $155\pm19$km/s. This places PG1307+085 local $M_{BH}-σ_*$ relation within the intrinsic scatter but offset towards a higher black hole mass with respect to the mean relat…
We present the multi epoch spectral analysis of HE 0436-4717, a bright Seyfert 1 galaxy serendipitously observed by the high energy satellite NuSTAR four times between December 2014 and December 2015. The source flux shows modest variability within each pointing and among the four observations. Spectra are well modelled in terms of a weakly variable primary power law with constant photon index ($Γ$=2.01$\pm$0.08). A constant narrow \ion{Fe} K$α$ emission line suggests that this feature has an origin far from the central black hole, while a broad relativistic component is not required by the da…
Measuring the star-forming properties of AGN hosts is key to our understanding of galaxy formation and evolution. However, this topic remains debated, partly due to the difficulties in separating the infrared (i.e. 1--1000 $μ$m) emission into AGN and star-forming components. Taking advantage of archival far-infrared data from Herschel, we present a new set of AGN and galaxy infrared templates, and introduce the spectral energy distribution fitting code IRAGNSEP. Both can be used to measure infrared host galaxy properties, free of AGN contamination. To build these, we used a sample of 100 local…
We study the physical and dynamical properties of the ionized gas in the prototypical HII galaxy Henize 2-10 using MUSE integral field spectroscopy. The large scale dynamics is dominated by extended outflowing bubbles, probably the results of massive gas ejection from the central star forming regions. We derive a mass outflow rate dMout/dt~0.30 Msun/yr, corresponding to mass loading factor eta~0.4, in range with similar measurements in local LIRGs. Such a massive outflow has a total kinetic energy that is sustainable by the stellar winds and Supernova Remnants expected in the galaxy. We use cl…
Hydrodynamical simulations of galaxy formation and evolution attempt to fully model the physics that shapes galaxies. The agreement between the morphology of simulated and real galaxies, and the way the morphological types are distributed across galaxy scaling relations are important probes of our knowledge of galaxy formation physics. Here we propose an unsupervised deep learning approach to perform a stringent test of the fine morphological structure of galaxies coming from the Illustris and IllustrisTNG (TNG100 and TNG50) simulations against observations from a subsample of the Sloan Digita…
We analyze radial stellar metallicity and kinematic profiles out to 1Re in 244 CALIFA galaxies ranging from morphological type E to Sd, to study the evolutionary mechanisms of stellar population gradients. We find that linear metallicity gradients exhibit a clear correlation with galaxy morphological type - with early type galaxies showing the steepest gradients. We show that the metallicity gradients simply reflect the local mass-metallicity relation within a galaxy. This suggests that the radial stellar population distribution within a galaxys effective radius is primarily a result of the \e…
Time series observations of a single dithered field centered on the diffuse dwarf satellite galaxy Crater II were obtained with the Dark Energy Camera (DECam) at the 4m Blanco Telescope at Cerro Tololo Inter-American Observatory, Chile, uniformly covering up to two half-light radii. Analysis of the $g$ and $i$ time series results in the identification and characterization of 130 periodic variable stars, including 98 RR Lyrae stars, 7 anomalous Cepheids, and 1 SX Phoenicis star belonging to the Crater II population, and 24 foreground variables of different types. Using the large number of ab-ty…
Only a handful of galaxies in the local Universe appear to be very young. We estimate the fraction of very young galaxies (VYGs), defined as those with more than half their stellar masses formed within the last Gyr. We fit non-parametric star formation histories (SFHs) to ~280 000 galaxy spectra from a flux- and volume-limited subsample of the Main Galaxy Sample (MGS) of the SDSS, which is also complete in mass-to-light ratio, thus properly accounting for passive galaxies of a given mass. The VYG fractions decrease with increasing galaxy stellar mass, from ~50% at $m = 10^8\,\rm M_\odot$ to ~0…
