A5044660520- Galaxies: Formation, Evolution, Phenomena
- Astronomy and Astrophysical Research
- Stellar, planetary, and galactic studies
- Astrophysics and Star Formation Studies
- Radio Astronomy Observations and Technology
- Astronomical Observations and Instrumentation
- Astrophysics and Cosmic Phenomena
- Gamma-ray bursts and supernovae
- Spectroscopy and Laser Applications
- Adaptive optics and wavefront sensing
- Scientific Research and Discoveries
- Astrophysical Phenomena and Observations
- Calibration and Measurement Techniques
- Astro and Planetary Science
- Particle Accelerators and Free-Electron Lasers
- Cosmology and Gravitation Theories
- History and Developments in Astronomy
- Pulsars and Gravitational Waves Research
- Particle Detector Development and Performance
- Data Visualization and Analytics
- Impact of Light on Environment and Health
- Plant Water Relations and Carbon Dynamics
- Superconducting and THz Device Technology
- Advanced Fluorescence Microscopy Techniques
- Laser Design and Applications
University of Groningen
2016-2025
Astronomical Institute of the Slovak Academy of Sciences
1995-2025
Tata Institute of Fundamental Research
2017-2021
National Centre for Radio Astrophysics
2016-2021
Astronomy and Space
2010-2020
Rutgers, The State University of New Jersey
2018
University of Louisville
2018
Leiden University
1991-2018
International Centre for Radio Astronomy Research
2018
The University of Western Australia
2018
We describe the design and construction of a formatted fiber field unit, SparsePak, characterize its optical astrometric performance. This array is optimized for spectroscopy low surface brightness extended sources in visible near‐infrared. SparsePak contains 82, 4 7 fibers subtending an area 72'' × 71'' telescope focal plane feeds WIYN Bench Spectrograph. Together, these instruments are capable achieving spectral resolutions λ/Δλ∼20,000 area–solid angle product ∼140 arcsec2 m2 per fiber....
This paper investigates the statistical properties of Tully-Fisher (TF) relations for a volume-limited complete sample spiral galaxies in nearby Ursa Major Cluster. The merits B, R, I, and K' surface photometry availability detailed kinematic information from H I synthesis imaging have been exploited. In addition to corrected global profile widths W, available rotation curves allow direct measurements observed maximum rotational velocities Vmax amplitudes Vflat outer flat parts. dynamical...
We investigate the effect of ram-pressure from intracluster medium on stripping H i gas in galaxies a massive, relaxed, X-ray bright, galaxy cluster at z = 0.2 Blind Ultra Deep Environmental Survey (BUDHIES). use cosmological simulations, and velocity versus position phase-space diagrams to infer orbital histories galaxies. In particular, we embed simple analytical description simulations identify regions where are more likely have been sufficiently stripped their fall below detection limit...
In this data paper we present the results of an extensive 21 cm-line synthesis imaging survey 43 spiral galaxies in nearby Ursa Major cluster using Westerbork Synthesis Radio Telescope. Detailed kinematic information form position-velocity diagrams and rotation curves is presented atlas together with HI channel maps, cm continuum global profiles, radial surface density integrated column velocity fields. The relation between corrected linewidth rotational velocities Vflat as derived from...
PPak is a new fiber‐based integral field unit (IFU) developed at the Astrophysical Institute of Potsdam and implemented as module into existing Multi‐Aperture Spectrophotometer (PMAS) spectrograph. The purpose to provide an extended view with large light‐collecting power for each spatial element, well adequate spectral resolution. system consists fiber bundle 331 object fibers, 36 sky 15 calibration fibers. fibers collect light from focal plane behind reducer lens. PPak, 2 7 in diameter,...
PPak is a new fiber-bundle, developed at the Astrophysical Institute Potsdam for existing PMAS 3D-instrument. The intention of to provide large integral field-of-view in combination with collecting area per fiber study extended low-surface brightness objects. system consists focal reducer lens and bundle, featuring an innovative design object, sky calibration fibers. With 74 x 65 arcseconds, currently world's widest field unit that provides semi-contiguous regular sampling astronomical Its...
Magnitude-limited samples of spiral galaxies drawn from the Ursa Major and Pisces Clusters are used to determine their extinction properties as a function inclination. Imaging photometry is available for 87 spirals in B, R, I, K' bands. Extinction causes systematic scatter color-magnitude plots. A strong luminosity dependence found. Relative edge-on face-on up 1.7 mag found at B most luminous but unmeasurably small faint galaxies. At R differential absorption with inclination reaches 1.3...
We present the preliminary design of WEAVE next generation spectroscopy facility for William Herschel Telescope (WHT), principally targeting optical ground-based follow up upcoming (LOFAR) and spacebased (Gaia) surveys. is a multi-object multi-IFU utilizing new 2 degree prime focus field view at WHT, with buffered pick place positioner system hosting 1000 (MOS) fibres or to 30 integral units each observation. The are fed single spectrograph, pair 8k(spectral) x 6k (spatial) pixel cameras,...
We describe and discuss the selection procedure statistical properties of galaxy sample used by Calar Alto Legacy Integral Field Area Survey (CALIFA), a public legacy survey 600 galaxies using integral field spectroscopy. The CALIFA "mother sample" was selected from Sloan Digital Sky (SDSS) DR7 photometric catalogue to include all with an r-band isophotal major axis between 45" 79.2" redshift 0.005 < z 0.03. mother contains 939 objects, which will be observed in course survey. targets for...
A comprehensive analysis of 355 high-quality Westerbork Synthesis Radio Telescope (WSRT) H i 21-cm line maps nearby galaxies shows that the properties and incident rate damped Lyman α absorption systems (DLAs) observed in spectra high-redshift QSOs are good agreement with DLAs originating gas discs like those z≈ 0 population. Comparison low-z DLA statistics incidence column density distribution f(NH i) for local galaxy sample no evidence evolution integral 'cross-section density'〈nσ〉=l−1 (l=...
We present a survey of the mass surface density spiral disks, motivated by outstanding uncertainties in rotation-curve decompositions. Our method exploits integral-field spectroscopy to measure stellar and gas kinematics nearly face-on galaxies sampled at 515, 660, 860 nm, using custom-built SparsePak PPak instruments. A two-tiered sample, selected from UGC, includes 146 galaxies, with B < 14.7 disk scale lengths between 10 20 arcsec, for which we have obtained Hα velocity fields;...
We present dynamically-determined rotation-curve mass decompositions of 30 spiral galaxies, which were carried out to test the maximum-disk hypothesis and quantify properties their dark-matter halos. used measured vertical velocity dispersions disk stars calculate dynamical surface densities (Σdyn). By subtracting our observed atomic inferred molecular gas from Σdyn, we derived stellar (Σ∗), thus have absolute measurements all dominant baryonic components galaxies. Using K-band brightness...
Our current understanding of galaxy evolution still has many uncertainties associated with the details accretion, processing, and removal gas across cosmic time. The next generation radio telescopes will image neutral hydrogen (HI) in galaxies over large volumes at high redshifts, which provide key insights into these processes. We are conducting COSMOS HI Large Extragalactic Survey (CHILES) Karl G. Jansky Very Array, is first survey to simultaneously observe from z=0 z~0.5. Here, we report...
We investigate the dynamics of starbursting dwarf galaxies, using both new and archival H I observations. consider 18 nearby galaxies that have been resolved into single stars by HST observations, providing their star formation history total stellar mass. find 9 objects a regularly rotating disk, 7 kinematically disturbed 2 show unsettled distributions. Two (NGC 5253 UGC 6456) velocity gradient along minor axis which we interpret as strong radial motions. For with disk derive rotation...
We present ionized-gas (OIII) and stellar kinematics (velocities velocity dispersions) for 30 nearly face-on spiral galaxies out to as much three disk scale lengths (h_R). These data have been derived from PPak IFU spectroscopy (4980-5370A), observed at a mean resolution of R=7700 (sigma_inst=17km/s). are fundamental product our survey will be used in companion papers to, e.g., derive the detailed (baryonic+dark) mass budget each galaxy sample. Our presentation provides comprehensive...
In a hierarchical Universe clusters grow via the accretion of galaxies from field, groups and even other clusters. As this happens, can lose their gas reservoirs different mechanisms, eventually quenching star-formation. We explore diverse environmental histories through multi-wavelength study combined effect ram-pressure stripping group "processing" in Abell 963, massive growing cluster at $z=0.2$ Blind Ultra Deep HI Environmental Survey (BUDHIES). incorporate hundreds new optical redshifts...
The MeerKAT Fornax Survey maps the distribution and kinematics of atomic neutral hydrogen gas (HI) in nearby galaxy cluster using telescope. 12 deg^2 survey footprint covers central region out to ~ Rvir stretches 2 towards south west include NGC 1316 group. HI column density sensitivity (3 sigma over 25 km/s) ranges from 5e+19/cm^2 at a resolution 10" (~ 1 kpc 20 Mpc distance Fornax) down 1e+18/cm^2 1' 6 kpc), slightly below this level lowest 100" 10 kpc). mass 50 is 6e+5 Msun. velocity 1.4...
The Ursa Major Cluster has received remarkably little attention, although it is as near the Virgo and contains a comparable number of H I-rich galaxies. In this paper, criteria for group membership are discussed data presented 79 galaxies identified with group. Of these, all have been imaged at B,R,I bands CCDs, 70 K' HgCdTe array detector, detected in HI 21 cm line. A complete sample 62 brighter than M_B_ = - 16.5 identified. Images gradients surface brightness color common linear scale. As...
There is accumulating evidence that the faint end of galaxy luminosity function might be very different in locations. The rising rich clusters and flat regions low density. If galaxies form according to model hierarchical clustering, then there should many small halos compared number big halos. this theory valid, must a mechanism eliminates at least visible component low-density regions. A plausible photoionization intergalactic medium time before epoch most dwarf but after formation for...
Strong bursts of star formation in galaxies may be triggered either by internal or external mechanisms. We study the distribution and kinematics H i gas outer regions 18 nearby starburst dwarf that have accurate histories from Hubble Space Telescope observations resolved stellar populations. find dwarfs show a variety morphologies, ranging heavily disturbed distributions with major asymmetries, long filaments, and/or i–stellar offsets to lopsided minor asymmetries. quantify asymmetry for...