Person: Nievas Rosillo, Mireia
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First Name
Mireia
Last Name
Nievas Rosillo
Affiliation
Universidad Complutense de Madrid
Faculty / Institute
Ciencias Físicas
Department
Estructura de la Materia, Física Térmica y Electrónica
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62 results
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Item First multi-wavelength campaign on the gamma-ray-loud active galaxy IC 310(Astronomy & astrophysics, 2017) Barrio Uña, Juan Abel; Bonnefoy, Simon Francois Albert; Contreras González, José Luis; Fonseca González, Mª Victoria; López Moya, Marcos; Nievas Rosillo, MireiaContext. The extragalactic very-high-energy gamma-ray sky is rich in blazars. These are jetted active galactic nuclei that are viewed at a small angle to the line-of-sight. Only a handful of objects viewed at a larger angle are so far known to emit above 100 GeV. Multi-wavelength studies of such objects up to the highest energies provide new insights into the particle and radiation processes of active galactic nuclei. Aims. We aim to report the results from the first multi-wavelength campaign observing the TeV detected nucleus of the active galaxy IC 310, whose jet is observed at a moderate viewing angle of 10 degrees-20 degrees. Methods. The multi-instrument campaign was conducted between 2012 November and 2013 January, and involved observations with MAGIC, Fermi, INTEGRAL, Swift, OVRO, MOJAVE and EVN. These observations were complemented with archival data from the AllWISE and 2MASS catalogs. A one-zone synchrotron self-Compton model was applied to describe the broadband spectral energy distribution. Results. IC 310 showed an extraordinary TeV flare at the beginning of the campaign, followed by a low, but still detectable TeV flux. Compared to previous measurements in this energy range, the spectral shape was found to be steeper during the low emission state. Simultaneous observations in the soft X-ray band showed an enhanced energy flux state and a harder-when-brighter spectral shape behavior. No strong correlated flux variability was found in other frequency regimes. The broad-band spectral energy distribution obtained from these observations supports the hypothesis of a double-hump structure. Conclusions. The harder-when-brighter trend in the X-ray and VHE emission, observed for the first time during this campaign, is consistent with the behavior expected from a synchrotron self-Compton scenario. The contemporaneous broadband spectral energy distribution is well described with a one-zone synchrotron self-Compton model using parameters that are comparable to those found for other gamma-ray-emitting misaligned blazars.Item Light Pollution Spanish REECL SQM Network(2015) Zamorano Calvo, Jaime; Sánchez de Miguel, Alejandro; Nievas Rosillo, Mireia; Tapia Ayuga, Carlos; Ocaña González, Francisco; Izquierdo Gómez, Jaime; Gallego Maestro, Jesús; Pascual Ramírez, SergioThe SQM network of the Spanish Light Pollution Research collaboration (http://guaix.fis.ucm.es/splpr/SQM-REECL) is growing with the help of amateur astronomers and interested citizens. Up to now there are 18 stations. SQM photometers provide measures of the night sky brightness every night using the PySQM software. The analysis of the data provided by the photometers allows the researchers to monitor the nightly, monthly and yearly evolution of the NSB and the relationship with sources of light pollution in intensity and distance. The photometers that are measuring in protected areas will alarm the researchers about eventual increasing of light pollution that could affect the environment. Using models of light dispersion on the atmosphere one can determine which light pollution sources are increasing the sky brightness at different places and in which extension. Networks of fixed photometers acquiring data every night are one of the main inputs to test these models.The collaborative effort of many people (citizen science) pro-vides the necessary data to derive scientific results.Item MAGIC detection of very high energy gamma-ray emission from the low-luminosity blazar 1ES 1741+196(Monthly notices of the Royal Astronomical Society, 2017) Antoranz Canales, Pedro; Barrio Uña, Juan Abel; Contreras González, José Luis; Domínguez, A.; Fidalgo, D.; Fonseca González, Mª Victoria; López Moya, Marcos; Miranda Pantoja, José Miguel; Nievas Rosillo, MireiaWe present the first detection of the nearby (z=0.084) low-luminosity BL Lac object 1ES 1741+196 in the very high energy (VHE: E>100 GeV) band. This object lies in a triplet of interacting galaxies. Early predictions had suggested 1ES 1741+196 to be, along with several other high-frequency BL Lac sources, within the reach of MAGIC detectability. Its detection by MAGIC, later confirmed by VERITAS, helps to expand the small population of known TeV BL Lacs. The source was observed with the MAGIC telescopes between 2010 April and 2011 May, collecting 46 h of good quality data. These observations led to the detection of the source at 6.0 σ confidence level, with a steady flux F(> 100 GeV) = (6.4 ± 1.7_(stat) ± 2.6_(syst)) • 10^(−12) ph cm^(−2) s^( −1) and a differential spectral photon index Γ = 2.4 ± 0.2_(stat) ± 0.2_(syst) in the range of ∼80 GeV - 3 TeV. To study the broad-band spectral energy distribution (SED) simultaneous with MAGIC observations, we use KVA, Swift/UVOT and XRT, and Fermi/LAT data. One-zone synchrotron-self-Compton (SSC) modeling of the SED of 1ES 1741+196 suggests values for the SSC parameters that are quite common among known TeV BL Lacs except for a relatively low Doppler factor and slope of electron energy distribution. A thermal feature seen in the SED is well matched by a giant elliptical’s template. This appears to be the signature of thermal emission from the host galaxy, which is clearly resolved in optical observations.Item Probing the Diffuse Optical-IR Background with TeV Blazars Detected with the MAGIC Telescopes(Frontiers in astronomy and space sciences, 2017) Prandini, Elisa; Domínguez Díaz, Alberto; Ramazani, Vandad Fallah; Hassan, Tarek; Mazin, Daniel; Moralejo, Abelardo; Nievas Rosillo, Mireia; Vanzo, Gaia; Vazquez Acosta, MonicaBlazars are radio loud quasars whose jet points toward the observer. The observed emission is mostly non-thermal, dominated by the jet emission, and in some cases extends up to the very high energy gamma rays (VHE; E > 100 GeV). To date, more than 60 blazars have been detected at VHE mainly with ground-based imaging atmospheric Cherenkov telescopes (IACTs) such as MAGIC, H.E.S.S., and VERITAS. Energetic photons from a blazar may interact with the diffuse optical and IR background (the extragalactic background light, EBL) leaving an imprint on the blazar energy spectrum. This effect can be used to constrain the EBL, with basic assumptions on the intrinsic energy spectrum. Current generation of IACTs is providing valuable measurements of the EBL density and energy spectrumfromoptical to infrared frequencies. In this contribution, we present the latest results obtained with the data taken with the MAGIC telescopes: using 32 spectra from 12 blazars, the scale factor of the optical density predicted by the EBL model from Dominguez et al. (2011) is constrained to be 0.95 (+0.11, -0.12)_(stat) (+0.16, -0.07)_(sys), where a value of 1 means the perfect match with the model.Item Multimessenger observations of a flaring blazar coincident with high-energy neutrino IceCube-170922A(Science, 2018) Domínguez Díaz, Alberto; Barrio Uña, Juan Abel; Contreras González, José Luis; Fonseca González, María Victoria; López Moya, Marcos; Nievas Rosillo, Mireia; Fidalgo, David; Sivakoff, Gregory; American Association for the Advancement of ScienceNeutrino emission from a flaring blazar Neutrinos interact only very weakly with matter, but giant detectors have succeeded in detecting small numbers of astrophysical neutrinos. Aside from a diffuse background, only two individual sources have been identified: the Sun and a nearby supernova in 1987. A multiteam collaboration detected a high-energy neutrino event whose arrival direction was consistent with a known blazar—a type of quasar with a relativistic jet oriented directly along our line of sight. The blazar, TXS 0506+056, was found to be undergoing a gamma-ray flare, prompting an extensive multiwavelength campaign. Motivated by this discovery, the IceCube collaboration examined lower-energy neutrinos detected over the previous several years, finding an excess emission at the location of the blazar. Thus, blazars are a source of astrophysical neutrinos.Item Multiband variability studies and novel broadband SED modeling of Mrk 501 in 2009(Astronomy & astrophysics, 2017) Antoranz Canales, Pedro; Barrio Uña, Juan Abel; Bonnefoy, Simon Francois Albert; Contreras González, José Luis; Domínguez, A.; Fidalgo, D.; Fonseca González, Mª Victoria; López Moya, Marcos; Miranda Pantoja, José Miguel; Nievas Rosillo, MireiaAims. We present an extensive study of the BL Lac object Mrk 501 based on a data set collected during the multi-instrument campaign spanning from 2009 March 15 to 2009 August 1, which includes, among other instruments, MAGIC, VERITAS, Whipple 10 m, and Fermi-LAT to cover the γ-ray range from 0.1 GeV to 20 TeV, RXTE and Swift to cover wavelengths from UV to hard X-rays, and GASP-WEBT that provides coverage of radio and optical wavelengths. Optical polarization measurements were provided for a fraction of the campaign by the Steward and St.Petersburg observatories. We evaluate the variability of the source and interband correlations, the γ-ray flaring activity occurring in May 2009, and interpret the results within two synchrotron self-Compton (SSC) scenarios. Methods. The multiband variability observed during the full campaign is addressed in terms of the fractional variability, and the possible correlations are studied by calculating the discrete correlation function for each pair of energy bands, where the significance was evaluated with dedicated Monte Carlo simulations. The space of SSC model parameters is probed following a dedicated grid-scan strategy, allowing for a wide range of models to be tested and offering a study of the degeneracy of model-to-data agreement in the individual model parameters, hence providing a less biased interpretation than the “single-curve SSC model adjustment” typically reported in the literature. Results. We find an increase in the fractional variability with energy, while no significant interband correlations of flux changes are found on the basis of the acquired data set. The SSC model grid-scan shows that the flaring activity around May 22 cannot be modeled adequately with a one-zone SSC scenario (using an electron energy distribution with two breaks), while it can be suitably described within a two-independent-zone SSC scenario. Here, one zone is responsible for the quiescent emission from the averaged 4.5-month observing period, while the other one, which is spatially separated from the first, dominates the flaring emission occurring at X-rays and very high energy (> 100 GeV, VHE) γ-rays. The flaring activity from May 1, which coincides with a rotation of the electric vector polarization angle (EVPA), cannot be satisfactorily reproduced by either a one-zone or a two-independent-zone SSC model, yet this is partially affected by the lack of strictly simultaneous observations and the presence of large flux changes on sub-hour timescales (detected at VHE γ-rays). Conclusions. The higher variability in the VHE emission and lack of correlation with the X-ray emission indicate that, at least during the 4.5-month long observing campaign in 2009, the highest-energy (and most variable) electrons that are responsible for the VHE γ-rays do not make a dominant contribution to the ∼1 keV emission. Alternatively, there could be a very variable component contributing to the VHE γ-ray emission in addition to that coming from the SSC scenario. The studies with our dedicated SSC grid-scan show that there is some degeneracy in both the one-zone and the two-zone SSC scenarios probed, with several combinations of model parameters yielding a similar model-to-data agreement, and some parameters better constrained than others. The observed γ-ray flaring activity, with the EVPA rotation coincident with the first γ-ray flare, resembles those reported previously for low frequency peaked blazars, hence suggesting that there are many similarities in the flaring mechanisms of blazars with different jet properties.Item PySQM the UCM open source software to read, plot and store data from SQM photometers(2014) Nievas Rosillo, Mireia; Zamorano Calvo, JaimeA multi platform software (PySQM) has been designed to read, store and plot data from Unihedron SQM-LE and SQM-LU photometers. It is intended to record night sky brightness data obtained with fixed SQM photometers. PySQM is distributed as open source software.Item Prospects for Cherenkov Telescope Array observations of the young supernova remnant RX J1713.7-3946(Astrophysical journal, 2017) Arqueros Martínez, Fernando; Barrio Uña, Juan Abel; Contreras González, José Luis; Franco Peláez, Francisco Javier; López Moya, Marcos; Mirabal Barrios, Néstor; Nievas Rosillo, Mireia; Rosado Vélez, Jaime; Tejedor Álvarez, Luis ÁngelWe perform simulations for future Cherenkov Telescope Array (CTA) observations of RX J1713.7−3946, a young supernova remnant (SNR) and one of the brightest sources ever discovered in very high energy (VHE) gamma rays. Special attention is paid to exploring possible spatial (anti)correlations of gamma rays with emission at other wavelengths, in particular X-rays and CO/H I emission. We present a series of simulated images of RX J1713.7−3946 for CTA based on a set of observationally motivated models for the gamma-ray emission. In these models, VHE gamma rays produced by high-energy electrons are assumed to trace the nonthermal X-ray emission observed by XMM-Newton, whereas those originating from relativistic protons delineate the local gas distributions. The local atomic and molecular gas distributions are deduced by the NANTEN team from CO and H I observations. Our primary goal is to show how one can distinguish the emission mechanism(s) of the gamma rays (i.e., hadronic versus leptonic, or a mixture of the two) through information provided by their spatial distribution, spectra, and time variation. This work is the first attempt to quantitatively evaluate the capabilities of CTA to achieve various proposed scientific goals by observing this important cosmic particle accelerator.Item Multi-wavelength characterization of the blazar S5 0716+714 during an unprecedented outburst phase(Astronomy & astrophysics, 2018) Barrio Uña, Juan Abel; Contreras González, José Luis; Domínguez Díaz, Alberto; Carreto Fidalgo, David Friedrich; Fonseca González, Victoria; Nievas Rosillo, Mireia; otros, ...Context. The BL Lac object S5 0716+714, a highly variable blazar, underwent an impressive outburst in January 2015 (Phase A), followed by minor activity in February (Phase B). The MAGIC observations were triggered by the optical flux observed in Phase A, corresponding to the brightest ever reported state of the source in the R-band. Aims.The comprehensive dataset collected is investigated in order to shed light on the mechanism of the broadband emission. Methods. Multi-wavelength light curves have been studied together with the broadband spectral energy distributions (SEDs). The sample includes data from Effelsberg, OVRO, Metsahovi, VLBI, CARMA, IRAM, SMA, Swift-UVOT, KVA, Tuorla, Steward, RINGO3, KANATA, AZT-8+ST7, Perkins, LX-200, Swift-XRT, NuSTAR, Fermi-LAT and MAGIC. Results. The flaring state of Phase A was detected in all the energy bands, providing for the first time a multi-wavelength sample of simultaneous data from the radio band to the very-high-energy (VHE, E> 100 GeV). In the constructed SED, the Swift-XRT +NuSTAR data constrain the transition between the synchrotron and inverse Compton components very accurately, while the second peak is constrained from 0.1 GeV to 600 GeV by Fermi+MAGIC data. The broadband SED cannot be described with a one-zone synchrotron self-Compton model as it severely underestimates the optical flux in order to reproduce the X-ray to y-ray data. Instead we use a two-zone model. The electric vector position angle (EVPA) shows an unprecedented fast rotation. An estimation of the redshift of the source by combined high-energy (HE, 0.1 GeV < E < 100 GeV) and VHE data provides a value of ,z = 0.31 +/- 0.02(stats) +/- 0.05(sys), confirming the literature value. Conclusions. The data show the VHE emission originating in the entrance and exit of a superluminal knot in and out of a recollimation shock in the inner jet. A shock-shock interaction in the jet seems responsible for the observed flares and EVPA swing. This scenario is also consistent with the SED modeling.Item Gamma-ray flaring activity of NGC 1275 in 2016-2017 measured by MAGIC(Astronomy & astrophysics, 2018) Barrio Uña, Juan Abel; Contreras González, José Luis; Domínguez Díaz, Alberto; Carreto Fidalgo, David Friedrich; Fonseca González, Victoria; Hoang, Kim Dinh; López Moya, Marcos; Nievas Rosillo, Mireia; Peñil del Campo, Pablo; Saha, Lab; otros, ...We report on the detection of flaring activity from the Fanaroff-Riley I radio galaxy NGC 1275 in very-high-energy (VHE, E> 100 GeV) gamma rays with the Major Atmospheric Gamma Imaging Cherenkov (MAGIC) telescopes. The observations were performed between 2016 September and 2017 February, as part of a monitoring programme. The brightest outburst, with similar to 1.5 times the Crab Nebula flux above 100 GeV (C.U.), was observed during the night between 2016 December 31 and 2017 January 1. The flux is fifty times higher than the mean flux previously measured in two observational campaigns between 2009 October and 2010 February and between 2010 August and 2011 February. Significant variability of the day-by-day light curve was measured. The shortest flux-doubling timescale was found to be of (611 +/- 101) min. The spectra calculated for this period are harder and show a significant curvature with respect to the ones obtained in the previous campaigns. The combined spectrum of the MAGIC data during the strongest flare state and simultaneous data from the Fermi-LAT around 2017 January 1 follows a power law with an exponential cutoff at the energy (492 +/- 35) GeV. We further present simultaneous optical flux density measurements in the R-band obtained with the Kungliga Vetenskaps Akademien (KVA) telescope and investigate the correlation between the optical and gamma-ray emission. Due to possible internal pair-production, the fast flux variability constrains the Doppler factor to values that are inconsistent with a large viewing angle as observed in the radio band. We investigate different scenarios for the explanation of fast gamma-ray variability, namely emission from magnetospheric gaps, relativistic blobs propagating in the jet (mini-jets), or an external cloud (or star) entering the jet. We find that the only plausible model to account for the luminosities here observed would be the production of gamma rays in a magnetospheric gap around the central black hole, only in the eventuality of an enhancement of the magnetic field threading the hole from its equipartition value with the gas pressure in the accretion flow. The observed gamma-ray flare therefore challenges all the discussed models for fast variability of VHE gamma-ray emission in active galactic nuclei.