J. H. Knapen
A5009625318- Galaxies: Formation, Evolution, Phenomena
- Astronomy and Astrophysical Research
- Stellar, planetary, and galactic studies
- Astrophysics and Star Formation Studies
- Astronomical Observations and Instrumentation
- Astrophysical Phenomena and Observations
- Gamma-ray bursts and supernovae
- Adaptive optics and wavefront sensing
- Astrophysics and Cosmic Phenomena
- Scientific Research and Discoveries
- History and Developments in Astronomy
- Radio Astronomy Observations and Technology
- Astro and Planetary Science
- Spectroscopy and Laser Applications
- CCD and CMOS Imaging Sensors
- Advanced Vision and Imaging
- Phase Equilibria and Thermodynamics
- Remote Sensing in Agriculture
- Impact of Light on Environment and Health
- Blind Source Separation Techniques
- Advanced Measurement and Metrology Techniques
- Calibration and Measurement Techniques
- Solar and Space Plasma Dynamics
- Planetary Science and Exploration
- Plant Water Relations and Carbon Dynamics
Instituto de Astrofísica de Canarias
2015-2024
Universidad de La Laguna
2015-2024
Liverpool John Moores University
2018-2023
The Ohio State University
2023
IAC (United States)
1996-2015
Consejo Superior de Investigaciones Científicas
1994-2014
University of Hertfordshire
1999-2008
Université de Montréal
1995-2007
Universities UK
2006
Isaac Newton Group
2000-2004
We present an overview of a new integral field spectroscopic survey called MaNGA (Mapping Nearby Galaxies at Apache Point Observatory), one three core programs in the fourth-generation Sloan Digital Sky Survey (SDSS-IV) that began on 2014 July 1. will investigate internal kinematic structure and composition gas stars unprecedented sample 10,000 nearby galaxies. summarize essential characteristics instrument design context MaNGA's key science goals prototype observations to demonstrate...
The Spitzer Survey of Stellar Structure in Galaxies S^4G is an Exploration Science Legacy Program approved for the post-cryogenic mission. It a volume-, magnitude-, and size-limited (d < 40 Mpc, |b| > 30 degrees, m_(Bcorr) 15.5, D25>1') survey 2,331 galaxies using IRAC at 3.6 4.5 microns. Each galaxy observed 240 s mapped to 1.5 x D25. final mosaicked images have typical 1 sigma rms noise level 0.0072 0.0093 MJy / sr microns, respectively. Our azimuthally-averaged surface brightness profile...
The Spitzer Survey of Stellar Structure in Galaxies (S^4G) is a deep 3.6 and 4.5 μm imaging survey 2352 nearby (<40 Mpc) galaxies. We describe the S(^4)G data analysis pipeline 4, which dedicated to two-dimensional structural surface brightness decompositions images, using GALFIT3.0. Besides automatic 1-component Sersic fits, 2-component bulge + exponential disk we present human-supervised multi-component decompositions, include, when judged appropriate, central point source, bulge, disk,...
We present a new approach for estimating the 3.6 micron stellar mass-to-light ratio in terms of [3.6]-[4.5] colors old populations. Our avoids several largest sources uncertainty existing techniques. By focusing on mid-IR wavelengths, we gain virtually dust extinction-free tracer stars, avoiding need to adopt model correctly interpret optical or optical/NIR normally leveraged assign M/L. calibrating relation between NIR and GLIMPSE giant stars also avoid discrepancies predictions populations...
WEAVE, the new wide-field, massively multiplexed spectroscopic survey facility for William Herschel Telescope, will see first light in late 2022. WEAVE comprises a 2-degree field-of-view prime-focus corrector system, nearly 1000-multiplex fibre positioner, 20 individually deployable 'mini' integral field units (IFUs), and single large IFU. These systems feed dual-beam spectrograph covering wavelength range 366$-$959\,nm at $R\sim5000$, or two shorter ranges $R\sim20\,000$. After summarising...
Abstract Visual inspections of the first optical rest-frame images from JWST have indicated a surprisingly high fraction disk galaxies at redshifts. Here, we alternatively apply self-supervised machine learning to explore morphological diversity z ≥ 3. Our proposed data-driven representation scheme galaxy morphologies, calibrated on mock TNG50 simulation, is shown be robust noise and correlate well with physical properties simulated galaxies, including their 3D structure. We method...
The Euclid ERO showcase Euclid's capabilities in advance of its main mission by targeting 17 astronomical objects, including galaxy clusters, nearby galaxies, globular and star-forming regions. A total 24 hours observing time was allocated the early months operation, scientific community engaged through an public data release. We describe development pipeline to create visually compelling images while simultaneously meeting demands within launch leveraging a pragmatic data-driven strategy....
We present a detailed study of the bar fraction in CfA sample Seyfert galaxies and carefully selected control nonactive to investigate relation between presence bars nuclear activity. To avoid problems related classification Third Reference Catalogue (RC3), e.g., subjectivity, low resolution, contamination by dust, we have developed an objective method, which conservatively apply our new subarcsecond resolution near-infrared (NIR) imaging data set discussed first paper this series. are able...
We analyze the observed properties of nested and single stellar bar systems in disk galaxies. The 112 galaxies our sample comprise largest matched Seyfert vs. non-Seyfert nearby with complete near-infrared or optical imaging sensitive to lengthscales ranging from tens pc kpc. find that a significant fraction galaxies, 17% +/- 4%, has more than one bar, 28% 5% barred have bars. fractions appear be stable according reasonable changes adopted criteria. For these bars, we detect clear division...
One-third of present-day spirals host optically visible strong bars that drive their dynamical evolution. However, the fundamental question how evolve over cosmological times has yet to be resolved, and even frequency at intermediate redshifts remains controversial. We investigate out z ~ 1 drawing on a sample 1590 galaxies from Galaxy Evolution Morphologies SEDs survey, which provides morphologies Hubble Space Telescope Advanced Camera for Surveys (ACS) two-band images accurate COMBO-17...
We discuss the selection and observations of a large sample nearby galaxies, which we are using to quantify star formation activity in local Universe. The consists 334 galaxies across all Hubble types from S0/a Im with recession velocities between 0 3000 km s-1. basic data for each galaxy narrow band H[Nii] R-band imaging, derive rates, equivalent widths surface brightnesses, total magnitudes. A strong correlation is found rate type, strongest isolated occurring Sc Sbc types. More...
Properties of bars and bulges in the Hubble sequence are discussed, based on an analysis 216 disc galaxies S0-Sm types (S0s from Near-Infrared S0 Survey spirals Ohio State University Bright Spiral Galaxy Survey). For this purpose we have collected, completed when necessary, various analyses previously made separately for early- late-type galaxies. We find strong evidence pseudo-bulges all types. Pseudo-bulges disc-like structures formed by secular evolutionary processes Similar to spirals,...
Photometric scaling relations are studied for S0 galaxies and compared with those obtained spirals. New two-dimensional multi-component decompositions presented 122 early-type disc galaxies, using deep Ks-band images. Combining them our previous decompositions, the final sample consists of 175 (Near-Infrared Survey S0s, NIRS0S: 117 S0s + 22 S0/a 36 Sa galaxies). As a comparison we use Ohio State University Bright Spiral Galaxy (OSUBSGS) nearly 200 spirals, which similar have previously been...
With the aim of constructing accurate 2D maps stellar mass distribution in nearby galaxies from S4G 3.6 and 4.5 micron images, we report on separation light old stars emission contributed by contaminants (e.g. hot dust 3.3 PAH feature). Results for a small sample six disk (NGC 1566, NGC 2976, 3031, 3184, 4321, 5194) with range morphological properties, contents star formation histories are presented to demonstrate our approach. We use an Independent Component Analysis (ICA) technique...
The Spitzer Survey of Stellar Structure in Galaxies (S4G) is the largest available database deep, homogeneous middle-infrared (mid-IR) images galaxies all types. survey, which includes 2352 nearby galaxies, reveals galaxy morphology only minimally affected by interstellar extinction. This paper presents an atlas and classifications S4G Comprehensive de Vaucouleurs revised Hubble-Sandage (CVRHS) system. CVRHS system follows precepts classical (1959) morphology, modified to include recognition...
An atlas of Ks-band images 206 early-type galaxies is presented, including 160 S0-S0/a galaxies, 12 ellipticals, and 33 Sa galaxies. A majority the Atlas belong to a magnitude-limited (mB<12.5 mag) sample 185 NIRS0S (Near-IR S0 galaxy Survey) To assure that mis-classified S0s are not omitted, 25 ellipticals from RC3 classified as in Carnegie were included sample. The 2-3 mag deeper than 2MASS images. Both visual photometric classifications made. Special attention paid classification lenses,...
The Spitzer Survey of Stellar Structure in Galaxies is a volume, magnitude, and size-limited survey 2352 nearby galaxies with deep imaging at 3.6 4.5 μm.In this paper, we describe our surface photometry pipeline showcase the associated data products that have released to community.We also identify physical mechanisms leading different levels central stellar mass concentration for same total mass.Finally, derive local mass-size relation μm morphologies.Our radial profiles reach densities...
The mid-infrared is an optimal window to trace stellar mass in nearby galaxies and the 3.6$\mu m$ IRAC band has been exploited this effect, but such estimates can be biased by dust emission. We present our pipeline reveal old flux at obtain maps for more than 1600 available from Spitzer Survey of Stellar Structure Galaxies (S$^{4}$G). This survey consists images two infrared bands (3.6 4.5$\mu m$), we use Independent Component Analysis (ICA) method presented Meidt et al. (2012) separate...
We present the most complete atlas of nuclear rings to date. include 113 found in 107 galaxies, six which are elliptical five highly inclined disc 18 unbarred and 78 barred galaxies. Star-forming occur 20% galaxies with types between T=-3 T=7. aim explore possible relationships size morphology various galactic parameters. produce colour index structure maps, as well Halpha Paalpha continuum-subtracted images from HST archival data. derive ellipticity profiles H-band 2MASS order detect bars...
We have analyzed the radial distribution of old stars in a sample 218 nearby face-on disks, using deep 3.6 μm images from Spitzer Survey Stellar Structure Galaxies. In particular, we studied structural properties those disks with broken or down-bending profile. find that, on average, genuine single-exponential profile scale length and central surface brightness which are intermediate to inner outer components disk same total stellar mass. particular case barred galaxies, ratio between break...
We present the first data release of high-resolution ($\leq0.2$ arcsec) 1.5-GHz radio images 103 nearby galaxies from Palomar sample, observed with eMERLIN array, as part LeMMINGs survey. This sample includes which are active (LINER and Seyfert) quiescent (HII Absorption line galaxies, ALG), reclassified based upon revised emission-line diagrams. detect emission $\gtrsim$ 0.2 mJy for 47/103 (22/34 LINERS, 4/4 Seyferts, 16/51 HII 5/14 ALGs) sizes typically $\lesssim$100 pc. identify core...
We describe selected highlights of the international conference ``The Central Kiloparsec Starbursts and AGN: The La Palma Connection'', held in May 2001 Los Cancajos on Spanish island Palma.