S. N. Molina
A5089124946- Astrophysics and Cosmic Phenomena
- Radio Astronomy Observations and Technology
- Gamma-ray bursts and supernovae
- Astrophysical Phenomena and Observations
- Neutrino Physics Research
- Dark Matter and Cosmic Phenomena
- Galaxies: Formation, Evolution, Phenomena
- Astronomical Observations and Instrumentation
- Astronomy and Astrophysical Research
- Solar and Space Plasma Dynamics
- Calibration and Measurement Techniques
- Stellar, planetary, and galactic studies
- Advanced Semiconductor Detectors and Materials
- Gyrotron and Vacuum Electronics Research
- Radio Wave Propagation Studies
- Infrastructure Maintenance and Monitoring
- Risk and Safety Analysis
- GNSS positioning and interference
- Business, Education, Mathematics Research
- Astrophysics and Star Formation Studies
- Pulsars and Gravitational Waves Research
- Photocathodes and Microchannel Plates
- Medical Imaging Techniques and Applications
- Business, Innovation, and Economy
- Particle Accelerators and Free-Electron Lasers
Instituto de Astrofísica de Andalucía
2011-2019
University of New Mexico
2016
Unidades Centrales Científico-Técnicas
2015
Consejo Superior de Investigaciones Científicas
2013-2015
Joint Institute for VLBI ERIC
2014
We present time-resolved broad-band observations of the quasar 3C 279 obtained from multi-wavelength campaigns conducted during first two years Fermi Gamma-ray Space Telescope mission. While investigating previously reported gamma-ray/optical flare accompanied by a change in optical polarization, we found that emission appears delayed with respect to gamma-ray about 10 days. X-ray reveal pair `isolated' flares separated ~90 days, only weak counterparts. The spectral structure measured...
We analyze the multifrequency behavior of quasar 3C 454.3 during three prominent \gamma-ray outbursts: 2009 Autumn, 2010 Spring, and Autumn. The data reveal a repeating pattern, including triple flare structure, in properties each outburst, which implies similar mechanism(s) location for all events. multi-frequency indicates that lower frequency events are co-spatial with outbursts, although emission varies on shortest timescales. determine variability from UV to IR wavelengths an outburst...
We analyze the parsec-scale jet kinematics from 2007 June to 2013 January of a sample $\gamma$-ray bright blazars monitored roughly monthly with Very Long Baseline Array at 43~GHz. In total 1929 images, we measure apparent speeds 252 emission knots in 21 quasars, 12 BL~Lacertae objects (BLLacs), and 3 radio galaxies, ranging 0.02$c$ 78$c$; 21\% are quasi-stationary. Approximately 1/3 moving execute non-ballistic motions, quasars exhibiting acceleration along within 5~pc (projected) core,...
We present observations of a major outburst at centimeter, millimeter, optical, X-ray, and γ-ray wavelengths the BL Lacertae object AO 0235+164. analyze timing multi-waveband variations in flux linear polarization, as well changes Very Long Baseline Array images λ = 7 mm with ∼0.15 milliarcsec resolution. The association events different wavebands is confirmed high statistical significance by probability arguments Monte Carlo simulations. A series sharp peaks optical pronounced maximum...
Since the launch of Fermi satellite, BL Lacertae has been moderately active at gamma-rays and optical frequencies until May 2011, when source started a series strong flares. The exceptional sampling achieved by GLAST-AGILE Support Program (GASP) Whole Earth Blazar Telescope (WEBT) in collaboration with Steward Observatory allows us to perform detailed comparison daily gamma-ray observations Fermi. Discrete correlation analysis between emission reveals time lag 0 +- 1 d, which suggests...
Since 2005, the blazar 3C 454.3 has shown remarkable flaring activity at all frequencies, and during last four years it exhibited more than one γ-ray flare per year, becoming most active in sky. We present for first time multi-wavelength AGILE, Swift, INTEGRAL, GASP-WEBT data collected order to explain extraordinary of which occurred 2010 November. On November 20 (MJD 55520), reached a peak flux (E >100 MeV) Fpγ = (6.8 ± 1.0) × 10−5 photons cm−2 s−1 on timescale about 12 hr, factor six...
Context. Over the past few years, on several occasions, large, continuous rotations of electric vector position angle (EVPA) linearly polarized optical emission from blazars have been reported. These events are often coincident with high energy γ-ray flares and they attracted considerable attention, since could allow us to probe magnetic field structure in emitting region jet. The flat-spectrum radio quasar 3C 279 is one most prominent examples showing this behaviour.
We present multiwavelength observations of 3C 454.3 from April 2008 to March 2010. The radio optical data are mostly the GASP-WEBT, UV and X-ray Swift, gamma-ray AGILE Fermi satellites. improved calibration optical-UV UVOT OM instruments estimated Lyalpha flux disentangle contributions different components in this spectral region. reveal prominent variability above 8 GHz. In band, amplitude decreases with increasing frequency due a steadier radiation both broad line region an accretion disc....
The quasar-type blazar 4C 38.41 (B3 1633+382) experienced a large outburst in 2011, which was detected throughout the entire electromagnetic spectrum. We present results of low-energy multifrequency monitoring by GASP project WEBT consortium and collaborators, as well those spectropolarimetric/spectrophotometric at Steward Observatory. also analyse high-energy observations Swift Fermi satellites. In optical-UV band, several indicate that there is contribution from QSO-like emission...
We perform a multi-wavelength polarimetric study of the quasar CTA 102 during an extraordinarily bright γ-ray outburst detected by Fermi Large Area Telescope in 2012 September–October when source reached flux F>100 MeV = 5.2 ± 0.4 × 10−6 photons cm−2 s−1. At same time, displayed unprecedented optical and near-infrared (near-IR) outburst. evolution parsec-scale jet with ultra-high angular resolution through sequence 80 total polarized intensity Very Long Baseline Array images at 43 GHz,...
We report on the first results of POLAMI program, a simultaneous 3.5 and 1.3mm full-Stokes-polarisation monitoring sample 36 brightest active galactic nuclei in northern sky with IRAM 30m Telescope. Through systematic statistical study data taken from October 2006 (from December 2009 for case observations) to August 2014, we characterise variability total flux density linear polarisation. find that all sources are highly variable at both 1.3mm, as well spectral index, is found be optically...
We describe the POLAMI program for monitoring of all four Stokes parameters a sample bright radio-loud active galactic nuclei with IRAM 30m telescope at 3.5 and 1.3mm. The started in October 2006 accumulated, until August 2014, 2300 observations 3.5mm, achieving median time sampling interval 22 days 37 sources. This first paper explains source selection, mostly blazars, observing strategy data calibration, gives details instrumental polarisation corrections. sensitivity (1sigma) reached...
After several years of quiescence, the blazar CTA 102 underwent an exceptional outburst in 2012 September–October. The flare was tracked from γ-ray to near-infrared (NIR) frequencies, including Fermi and Swift data as well photometric polarimetric observatories. An intensive Glast-Agile support programme Whole Earth Blazar Telescope (GASP–WEBT) collaboration campaign optical NIR bands, with addition previously unpublished archival extension through fall 2015, allows comparison this previous...
We analyse the circular polarisation data accumulated in first 7 years of POLAMI project introduced an accompanying paper (Agudo et al.). In 3mm wavelength band, we acquired more than 2600 observations, and all but one our 37 sample sources were detected, most them several times. For sources, observed distribution degree is broader that unpolarised calibrators, indicating weak (<0.5%) present time. Our detection rate maximum found, 2.0%, are comparable to previous surveys, made at much...
We report on long-term multi-wavelength monitoring of blazar Mrk 421 by the GASP-WEBT collaboration and Steward Observatory, Swift Fermi satellites. study source behaviour in period 2007-2015, characterized several extreme flares. The ratio between optical, X-ray, \gamma-ray fluxes is very variable. flux variations show fair correlation with optical ones starting from 2012. analyse spectropolarimetric data find wavelength-dependence polarisation degree (P), which compatible presence host...
We present the results of optical (R band) photometric and polarimetric monitoring Very Long Baseline Array (VLBA) imaging blazar S4 0954+658, along with Fermi gamma;-ray data during a multi-waveband outburst in 2011 March-April. After faint state brightness level R ~17.6 mag registered first half January 2011, source started to rise reached ~14.8 middle March, showing flare-like behavior. The most spectacular case intranight variability was observed night March 9, when brightened by ~0.7...
We present an analysis of the multiwavelength behaviour blazar OJ 248 at z = 0.939 in period 2006-2013. use low-energy data (optical, near-infrared, and radio) obtained by 21 observatories participating GLAST-AGILE Support Program (GASP) Whole Earth Blazar Telescope (WEBT), as well from Swift (optical-UV X-rays) Fermi (gamma-rays) satellites, to study flux spectral variability correlations among emissions different bands. take into account effect absorption Damped Lyman Alpha intervening...
The source NRAO 150 is a very prominent millimeter to radio emitting quasar at redshift z = 1.52 for which previous VLBI observations revealed fast counterclockwise rotation of the innermost regions jet. Here we present new polarimetric multi-epoch VLBI-imaging performed 8, 15, 22, 43, and 86 GHz with Very Long Baseline Array (VLBA), Global Millimeter (GMVA) between 2006 2010. All observational evidence – i.e., spectral index maps, image cross-correlation, low level linear polarization...
We use a combination of high-resolution very long baseline interferometry (VLBI) radio and multi-wavelength flux density polarization observations to constrain the physics dissipation mechanism powering broadband flares in 3C 279 during an episode extreme flaring activity 2013-2014. Six bright superimposed on long-term outburst are detected at $\gamma$-ray energies. Four have optical counterparts. The two modes (faster sitting top term outburst) present radio, optical, frequencies missing...
We present $\gamma$-ray, X-ray, ultraviolet, optical, and near-infrared light curves of 33 $\gamma$-ray bright blazars over four years that we have been monitoring since 2008 August with multiple ground-based telescopes the Swift satellite, augmented by data from Fermi Gamma-ray Space Telescope other publicly available Swift. The sample consists 21 flat-spectrum radio quasars (FSRQs) 12 BL Lac objects (BL Lacs). identify quiescent active states sources based on their behavior. derive optical...
The blazar 1156+295 was active at γ-ray energies, exhibiting three prominent flares during the year 2010. Here, we present results using combination of broad-band (X-ray through mm single-dish) monitoring data and radio-band imaging 43 GHz on connection events to ejections superluminal components other changes in jet 1156+295. kinematics over interval 2007.0–2012.5 Very Long Baseline Array observations reveal presence four moving one stationary component inner region jet. propagation third...
We present a multiwavelength study of the flat-spectrum radio quasar CTA 102 during 2013-2017. use radio-to-optical data obtained by Whole Earth Blazar Telescope, 15 GHz from Owens Valley Radio Observatory, 91 and 103 Atacama Large Millimeter Array, near-infrared Rapid Eye Monitor telescope, as well Swift (optical-UV X-rays) Fermi ($\gamma$ rays) satellites to flux spectral variability correlation between changes at different wavelengths. Unprecedented $\gamma$-ray flaring activity was...
ABSTRACT In this paper we describe a new approach for millimeter Very Long Baseline Interferometry (mm-VLBI) calibration that provides bona-fide astrometric alignment of the millimeter-wavelength images from single source, measurement frequency-dependent effects, such as “core-shifts” near black hole active galactic nucleus jets. We achieve our by solving first ionospheric (dispersive) contributions using wide-band centimeter-wavelength observations. Second, solve tropospheric...
Combined with very-long-baseline interferometry measurements, the observations of fast TeV gamma-ray flares probe structure and emission mechanism blazar jets. However, only a handful such have been detected to date, within last few years these observed from lower-frequency-peaked BL~Lac objects flat-spectrum radio quasars. We report on flare BL~Lacertae by VERITAS, rise time $\sim$2.3~hr decay $\sim$36~min. The peak flux above 200 GeV is $(4.2 \pm 0.6) \times 10^{-6} \;\text{photon}...