Resultados de investigación

Massive stars have an impact on their surroundings from early in their formation until the end of their lives. However, very little is known about their formation. Episodic accretion may play a crucial role in the process, but only a handful of observations have reported such events occurring in massive protostars. We aim to investigate the outburst event from the high-mass star-forming region S255IR where the protostar NIRS3 recently underwent an accretion outburst. We follow the evolution of this source both in photometry and morphology of its surroundings. We performed near infrared adaptive optics observations on the S255IR central region using the Large Binocular Telescope in the Ks broadband as well as the H_2_ and Br{gamma} narrow-band filters with an angular resolution of ~0.06arcsec, close to the diffraction limit. We discovered a new near infrared knot north-east of NIRS3 that we interpret as a jet knot that was ejected during the last accretion outburst and observed in the radio regime as part of a follow-up after the outburst. We measured a mean tangential velocity for this knot of 450+/-50km/s. We analysed the continuum-subtracted images from H_2_, which traces jet-shocked emission, and Br{gamma}, which traces scattered light from a combination of accretion activity and UV radiation from the central massive protostar. We observed a significant decrease in flux at the location of NIRS3, with K=13.48mag being the absolute minimum in the historic series. Our observations strongly suggest a scenario where the episodic accretion is followed by an episodic ejection response in the near infrared, as was seen in the earlier radio follow-up. The ~2um photometry from the past 30 years suggests that NIRS3 might have undergone another outburst in the late 1980s, making it the first massive protostar with such evidence observed in the near infrared., Reduced images from the Large Binocular Telescope (LBT) of the S255IR massive star-forming region. Below we give further details extracted from text in the paper. Observations were taken on 13 February 2022 with the Large Binocular Telescope (LBT), in particular the SX telescope with an 8.4m primary mirror and using the LBT Utility Camera in the Infrared (LUCI) instrument (programme ID: UV-2022A-004, PI: J.C. Tan). Adaptive optics assisted mode was used with the Single conjugated adaptive Optics Upgrade for LBT SOUL (Pinna et al., 2016, in Adaptive Optics Systems V, ed. E. Marchetti, L. M. Close, & J.-P. Veran, Vol. 9909, International Society for Optics and Photonics (SPIE), 99093V). The N30 camera with a pixel scale of 0.015arcsec and field of view (FoV) of 30arcsec*30arcsec was used. The filters Ks, H_2_), and Br{gamma}, which are centred at the wavelengths 2.163, 2.124, 2.170um, respectively, were employed. Images were centred around S255IR NIRS3, with central coordinates of the image RA(J2000)=06:12:54.355, Dec(J2000)=+17:59:23.748. The AO guide star we used (i.e. 2MASSJ06125505+1759289 RA(J2000)=06:12:55.049, Dec(J2000)=+17:59:28.896, R=14.8mag) is located 14arcsec from NIRS3. The Strehl ratio was 0.2, and the final full width half maximum (FWHM) at the position of the AO guide star was ~0.06arcsec for all three filters (derived by fitting Moffat profiles, namely, close to the LBT diffraction limit. The data were reduced and flux calibrated with custom Python scripts using the Python packages ccdproc, astropy and photutils. The flux calibration was performed by matching field stars with the UKIRT Infrared Deep Sky Survey (UKIDSS) point source catalogue, for which we achieved an accuracy of ~0.06mag. The data were astrometrically corrected by matching stars to the Gaia DR3 catalogue retrieved with astroquery. We were able to match seven Gaia stars in our FoV and have a final residual for the astrometry of 0.034arcsec., Financial support from the Severo Ochoa grant CEX2021-001131-S funded by MCIN/AEI/ 10.13039/501100011033, No

We present a new image of a 26.5 square degree region in the Bootes constellation obtained at 1.4GHz using the Aperture Tile in Focus (Apertif) system on the Westerbork Synthesis Radio Telescope. We use a newly developed processing pipeline which includes direction-dependent self-calibration which provides a significant improvement of the quality of the images compared to those released as part of the Apertif first data release. For the Bootes region, we mosaic 187 Apertif images and extract a source catalog. The mosaic image has an angular resolution of 27x11.5 arcsec and a median background noise of 40uJy/beam. The catalog has 8994 sources and is complete down to the 0.3mJy level. We combine the Apertif image with LOFAR images of the Bootes field at 54 and 150MHz to study spectral properties of the sources. We find a spectral flattening towards low flux density sources. Using the spectral index limits from Apertif non-detections we derive that up to 9% of the sources have ultra-steep spectra with a slope steeper than -1.2. Steepening of the spectral index with increasing redshift is also seen in the data showing a different dependency for the low-frequency spectral index and the high frequency one. This can be explained by a population of sources having concave radio spectra with a turnover frequency around the LOFAR band. Additionally, we discuss cases of individual extended sources with an interesting resolved spectral structure. With the improved pipeline, we aim to continue processing data from the Apertif wide-area surveys and release the improved 1.4GHz images of several famous fields., We extracted the Apertif source catalog using the Python Blob Detector and Source Finder (PyBDSF; Mohan & Rafferty 2015). Similar to Shimwell et al. (2019A&A...622A...1S, Cat. J/A+A/622/A1), we used a peak and island detection threshold of 5{sigma} and 4{sigma} respectively, and the size of a sliding box to estimate the local RMS was set to 30x30xbmaj, where bmaj is the major axis of the synthesized beam. We used the publicly available LOFAR HBA and LBA mosaic images and the corresponding catalogs of the Bootes area (Tasse et al. 2021A&A...648A...1T; Williams et al. 2021A&A...655A..40W, Cat. J/A+A/655/A40) and present spectral indices of the sources in table3., Financial support from the Severo Ochoa grant CEX2021-001131-S funded by MCIN/AEI/ 10.13039/501100011033, No

The geometries of near-resonant planetary systems offer a relatively pristine window into the initial conditions of exoplanet systems. Given that near-resonant systems have likely experienced minimal dynamical disruptions, the spin-orbit orientations of these systems inform the typical outcomes of quiescent planet formation, as well as the primordial stellar obliquity distribution. However, few measurements have been made to constrain the spin- orbit orientations of near-resonant systems. We present a Rossiter-McLaughlin measurement of the near-resonant warm Jupiter TOI-2202b, obtained using the Carnegie Planet Finder Spectrograph on the 6.5m Magellan Clay Telescope. This is the eighth result from the Stellar Obliquities in Long-period Exoplanet Systems survey. We derive a sky-projected 2D spin-orbit angle {lambda}=26_-15_^+12^ and a 3D spin-orbit angle {psi}=31_-11_^+13^deg , finding that TOI-2202 b-the most massive near- resonant exoplanet with a 3D spin-orbit constraint to date-likely deviates from exact alignment with the host star's equator. Incorporating the full census of spin-orbit measurements for near-resonant systems, we demonstrate that the current set of near-resonant systems with period ratios P2/P1<~4 is generally consistent with a quiescent formation pathway, with some room for low-level (<~20{deg}) protoplanetary disk misalignments or post-disk- dispersal spin-orbit excitation. Our result constitutes the first population- wide analysis of spin-orbit geometries for near-resonant planetary systems., "Our team measured the ingress of TOI-2202b's transit on UT 2022 August 24 using one of the 0.7m Minerva-Australis telescopes located at the University of Southern Queensland's Mount Kent Observatory. The telescope is equipped with a 2000x2000pixel Andor CCD with pixel scale 0.608"", and we used a 15pixel radius (9.12"") aperture to extract the photometry. We measured one partial transit of TOI-2202b on UT 2022 September 9 using the Las Cumbres Observatory Global Network (LCOGT) Siding Spring Observatory (SSO) 0.4 and 1m telescopes, in New South Wales in Australia. Observations were taken in the Sloan i' band with 170s exposures on the 0.4m telescope and 43s exposures on the 1m telescope. We also measured two transit ingress events for TOI-2202b on UT 2022 October 10 and 2022 October 10, as well as one full transit on UT 2022 November 4, using the LCOGT Cerro Tololo Inter-American Observatory (CTIO) 0.4m telescope located 80km east of La Serena, Chile. The UT 2022 October 10 ingress was simultaneously observed using the LCOGT CTIO 1m telescope. Observations were taken in the Sloan i' band, with 170s exposures for the 0.4m telescope observations and 43s exposures for the 1m telescope observations. We measured one transit egress event for TOI-2202b on UT 2022 October 11 using the TRAPPIST-South 0.6m robotic telescope at La Silla Observatory in the Atacama Desert of Chile. Continuous 30s observations were taken with the Astrodon ""i+z"" filter. The TRAPPIST-South observing sequence spanned 2.16hr prior to the transit ingress, as well as 1.76 in-transit hours of observations. Our team measured two full transits of TOI-2202b on UT 2022 October 23 and UT 2022 November 4 using the station of the Observatoire Moana located in El Sauce Observatory in Chile. Observations were taken in the Sloan r band with continuous 100s exposures.", Financial support from the Severo Ochoa grant CEX2021-001131-S funded by MCIN/AEI/ 10.13039/501100011033, No

Fast radio bursts are bright radio transients whose origins are not yet understood. The search for a multi-wavelength counterpart of those events can set a tight constraint on the emission mechanism and the progenitor source. We conducted a multi-wavelength observational campaign on FRB 20180916B between October 2020 and August 2021 over eight activity cycles of the source. Observations were carried out in the radio band by the SRT both at 336 and 1547MHz and the uGMRT at 400MHz. Simultaneous observations were conducted by the optical telescopes Asiago (Galileo and Copernico), CMO SAI MSU, CAHA 2.2m, RTT-150 and TNG, and X/gamma-ray detectors on board the AGILE, Insight-HXMT, INTEGRAL, and Swift satellites. We present the detection of 14 new radio bursts detected with the SRT at 336MHz and seven new bursts with the uGMRT from this source. We provide the deepest prompt upper limits in the optical band for FRB 20180916B to date. In fact, the TNG/SiFAP2 observation simultaneous to a burst detection by uGMRT gives an upper limit E_optical_-E_radio_<1.3x10^2^. Another burst detected by the SRT at 336MHz was also co-observed by Insight-HXMT. The non-detection in the X-rays yields an upper limit (1-30keV band) of E_X-ray_=E_radio_ in the range of (0.9-1.3)10^7^, depending on the model that is considered for the X-ray emission., We performed a MWL observing campaign on R3, focusing on different activity cycles, from 2020/10/23 to 2021/08/30., Financial support from the Severo Ochoa grant CEX2021-001131-S funded by MCIN/AEI/ 10.13039/501100011033, No

The loneliness of hot Jupiters supports the high-eccentricity migration as a primary path leading to the formation of systems with those planets stripped of any close-in planetary companions. Here we present the null results of searches for low-mass planets close to hot Jupiters in 10 planetary systems: HAT-P-4, HAT-P-10, HAT-P-12, HAT-P-17, HAT-P-19, HAT-P-32, HAT-P-44, Qatar-6, TrES-4, and WASP-48. We employed multi-sector time-series photometry from the Transiting Exoplanet Survey Satellite enhanced with new ground-based transit light curves to determine the sizes of hypothetical planets that might still avoid being detected. We redetermined transit parameters for the known hot Jupiters using a homogeneous approach. We refuted transit timing variations for HAT-P-12 b, claimed recently in the literature. The transit timing data permitted us to place tighter constraints on third bodies in HAT-P-19 and HAT-P-32 systems detected in Doppler measurements. We also study four multi-periodic pulsating variable stars in the field around HAT-P-17., We provide the photometric time series for transits of HAT-P-4 b, HAT-P-10 b, HAT-P-12 b, HAT-P-17 b, HAT-P-19 b, HAT-P-32 b, HAT-P-44 b, Qatar-6 b, TrES-4 b, and WASP-48 b acquired with the instruments: the 2.0m Liverpool Telescope (LT2.0) at Observatorio del Roque de los Muchachos (La Palma, Spain), the 1.5m Ritchey-Chretien Telescope (OSN1.5) at the Sierra Nevada Observatory (OSN, Spain), the 1.2m Cassegrain telescope (TRE1.2) at the Michael Adrian Observatory (Trebur, Germany), the 0.9m Ritchey-Chretien Telescope (OSN0.9) at the OSN, the 0.9/0.6m Schmidt Teleskop Kamera (JENA0.9) at the University Observatory Jena (Germany), and the 0.6m Cassegrain telescope (PIW0.6) at the Institute of Astronomy of the Nicolaus Copernicus University in Torun (Poland). The data were collected between 2015 and 2021. The details of observations and data processing are given in the source paper. We also provide details on the out-of-transit monitoring for four targets: HAT-P-10, HAT-P-17, HAT-P-44, and Qatar-6. The data were collected with the PIW0.6 telescope between 2016 and 2019. Further information is given in the source paper. We also provide the new mid-transit times determined from our ground-based light curves and from the TESS photometric time series. The re-determined mid-transit times from literature data are also given. For more details, see the paper., Financial support from the Severo Ochoa grant CEX2021-001131-S funded by MCIN/AEI/ 10.13039/501100011033, No

Observations of individual massive stars, super-luminous supernovae, gamma-ray bursts, and gravitational wave events involving spectacular black hole mergers indicate that the low-metallicity Universe is fundamentally different from our own Galaxy. Many transient phenomena will remain enigmatic until we achieve a firm understanding of the physics and evolution of massive stars at low metallicity (Z). The Hubble Space Telescope has devoted 500 orbits to observing ~250 massive stars at low Z in the ultraviolet (UV) with the COS and STIS spectrographs under the ULLYSES programme. The complementary X-Shooting ULLYSES (XShootU) project provides an enhanced legacy value with high-quality optical and near-infrared spectra obtained with the wide-wavelength coverage X-shooter spectrograph at ESO's Very Large Telescope. We present an overview of the XShootU project, showing that combining ULLYSES UV and XShootU optical spectra is critical for the uniform determination of stellar parameters such as effective temperature, surface gravity, luminosity, and abundances, as well as wind properties such as mass-loss rates as a function of Z. As uncertainties in stellar and wind parameters percolate into many adjacent areas of astrophysics, the data and modelling of the XShootU project is expected to be a game changer for our physical understanding of massive stars at low Z. To be able to confidently interpret James Webb Space Telescope spectra of the first stellar generations, the individual spectra of low-Z stars need to be understood, which is exactly where XShootU can deliver., In Table B.1 we present optical and NIR (JHK) photometry of the ULLYSES targets, as well as spectroscopic and multiplicity information. Table B.2 provides an extensive literature search for the stellar and wind parameters as they were known prior to the start of ULLYSES., Financial support from the Severo Ochoa grant CEX2021-001131-S funded by MCIN/AEI/ 10.13039/501100011033, No

We report the discovery of HN Lib b, a sub-Neptunian mass planet orbiting the nearby (d~6.25pc) M4.0 V star HN Lib detected by our CARMENES radial-velocity (RV) survey. We determined a planetary minimum mass of M_b_sini=5.46+/-0.75M_Earth_ and an orbital period of P_b_=36.116+/-0.029d, using ~5yr of CARMENES data, as well as archival RVs from HARPS and HIRES spanning more than 13yr. The flux received by the planet equals half the instellation on Earth, which places it in the middle of the conservative habitable zone (HZ) of its host star. The RV data show evidence for another planet candidate with M_[c]_sini=9.7+/-1.9M_Earth_ and P_[c]_=113.46+/-0.20d. The long-term stability of the signal and the fact that the best model for our data is a two-planet model with an independent activity component stand as strong arguments for establishing a planetary origin. However, we cannot rule out stellar activity due to its proximity to the rotation period of HN Lib, which we measured using CARMENES activity indicators and photometric data from a ground-based multi-site campaign as well as archival data. The discovery adds HN Lib b to the shortlist of super-Earth planets in the habitable zone of M dwarfs, but HN Lib [c] probably cannot be inhabited because, if confirmed, it would most likely be an icy giant., HN Lib was spectroscopically observed with CARMENES between 27 January 2016 and 31 December 2020, resulting in a total of 94 RV measurements. CARMENES is installed at the 3.5m telescope of the Calar Alto Observatory in Almeria (Spain). It was specifically designed to deliver high-resolution spectra at optical (resolving power R~94600) and near-infrared (R~80400) wavelengths covering the range from 520nm to 1710nm. CARMENES has two different channels, one for the optical (the VIS channel) and one for the near-infrared (the NIR channel) with a dichroic at 960nm. All data were acquired with integration times of 1800s, which is the maximum exposure time employed for precise RV measurements with CARMENES., Financial support from the Severo Ochoa grant CEX2021-001131-S funded by MCIN/AEI/ 10.13039/501100011033, No

We study the broadband emission of Mrk 501 using multiwavelength observations from 2017 to 2020 performed with a multitude of instruments, involving, among others, MAGIC, Fermi's Large Area Telescope (LAT), NuSTAR, Swift, GASP-WEBT, and the Owens Valley Radio Observatory. Mrk 501 showed an extremely low broadband activity, which may help to unravel its baseline emission. Nonetheless, significant flux variations are detected at all wave bands, with the highest occurring at X-rays and very-high-energy (VHE) {gamma}-rays. A significant correlation (>3{sigma}) between X-rays and VHE {gamma}-rays is measured, supporting leptonic scenarios to explain the variable parts of the emission, also during low activity. This is further supported when we extend our data from 2008 to 2020, and identify, for the first time, significant correlations between the Swift X-Ray Telescope and Fermi-LAT. We additionally find correlations between high-energy {gamma}-rays and radio, with the radio lagging by more than 100 days, placing the {gamma}-ray emission zone upstream of the radio-bright regions in the jet. Furthermore, Mrk 501 showed a historically low activity in X-rays and VHE {gamma}-rays from mid-2017 to mid-2019 with a stable VHE flux (>0.2TeV) of 5% the emission of the Crab Nebula. The broadband spectral energy distribution (SED) of this 2yr long low state, the potential baseline emission of Mrk 501, can be characterized with one-zone leptonic models, and with (lepto)-hadronic models fulfilling neutrino flux constraints from IceCube. We explore the time evolution of the SED toward the low state, revealing that the stable baseline emission may be ascribed to a standing shock, and the variable emission to an additional expanding or traveling shock., This study focuses on the multiwavelength (MWL) data collected from Mrk 501 during the 4yr period spanning from the beginning of the observational period in the year 2017 until the end of the observational period in the year 2020 (MJD 57754 to MJD 59214). The coordinated observations involve a large number of instruments, including FACT, MAGIC, Fermi-LAT, Swift, GLAST-AGILE Support Program (GASP)-Whole Earth Blazar Telescope (WEBT), and OVRO. Additionally, three 10hr long observations with NuSTAR yielded a precise measurement of the falling segment of the low-energy bump, which is expected to be dominated by the highest-energy electrons at the source., Financial support from the Severo Ochoa grant CEX2021-001131-S funded by MCIN/AEI/ 10.13039/501100011033, No

We present a Spitzer/Herschel focused survey of the Aquila molecular clouds (d~436pc) as part of the eHOPS (extension of the Herschel orion protostar survey, or HOPS, Out to 500 ParSecs) census of nearby protostars. For every source detected in the Herschel/PACS bands, the eHOPS-Aquila catalog contains 1-850{mu}m SEDs assembled from the Two Micron All Sky Survey, Spitzer, Herschel, the Wide-field Infrared Survey Explorer, and James Clerk Maxwell Telescope/SCUBA-2 data. Using a newly developed set of criteria, we classify objects by their SEDs as protostars, pre-main-sequence stars with disks, and galaxies. A total of 172 protostars are found in Aquila, tightly concentrated in the molecular filaments that thread the clouds. Of these, 71 (42%) are Class 0 protostars, 54 (31%) are Class I protostars, 43 (25%) are flat-spectrum protostars, and four (2%) are Class II sources. Ten of the Class 0 protostars are young PACS bright red sources similar to those discovered in Orion. We compare the SEDs to a grid of radiative transfer models to constrain the luminosities, envelope densities, and envelope masses of the protostars. A comparison of the eHOPS-Aquila to the HOPS protostars in Orion finds that the protostellar luminosity functions in the two star-forming regions are statistically indistinguishable, the bolometric temperatures/envelope masses of eHOPS-Aquila protostars are shifted to cooler temperatures/higher masses, and the eHOPS-Aquila protostars do not show the decline in luminosity with evolution found in Orion. We briefly discuss whether these differences are due to biases between the samples, diverging star formation histories, or the influence of environment on protostellar evolution., This paper presents SEDs assembled from photometry and spectra covering a wavelength range of 1-850um. These come from multiple catalogs. The photometry from 1-24um is from the Spitzer Extended Solar Neighborhood Archive (SESNA) catalog compiled by R. Gutermuth et al. (2022, in preparation). The SESNA data products are publicly available through http://bit.ly/sesna2021 We use observations from the Herschel Space Observatory to extract photometry in the 70-500um wavelength region. We obtain the observations from the Herschel Science Archive. We provide the observational details such as observation IDs, observed wavelengths, proposal names, and scan velocities for these observations in Appendix A (Tables 7 and 8). The 850um photometry is from maps made with the Submillimeter Common-User Bolometer Array-2 (SCUBA-2) instrument on the James Clerk Maxwell Telescope (JCMT). We use the 850um flux maps from the JCMT Gould Belt Survey data release repository (Kirk+ 2018ApJS..238....8K ; doi: 10.11570/18.0005). When available, we complement the Spitzer photometry with the spectroscopic measurements from the Infrared Spectrograph (IRS) on Spitzer using the Short-Low (SL; 5.2-14um) and Long-Low (LL; 14-38um) modules, both having a low spectral resolution of about 90. We obtain the IRS observation from the Combined Atlas of Sources with Spitzer IRS Spectra (CASSIS). We also utilize mid-IR photometry from the Wide-field Infrared Survey Explorer (WISE). The WISE photometry is retrieved from the AllWISE catalog (see II/328) in the NASA/IPAC Infrared Science Archive (IRSA). After following the steps from Sections 4.1.2-4.1.6, we find a total of 172 protostars (Table 2), 73 pre-main-sequence (pre-MS) stars with disks (Table 9), 24 reddened pre-MS stars with disks (Table 9), 118 galaxies (Table 10), and 12 candidate protostars (Table 11)., Financial support from the Severo Ochoa grant CEX2021-001131-S funded by MCIN/AEI/ 10.13039/501100011033, No

One of the most reliable means of studying the stellar interior is through the apsidal motion in double line eclipsing binary systems since these systems present errors in masses, radii, and effective temperatures of only a few per cent. On the other hand, the theoretical values of the apsidal motion to be compared with the observed values depend on the stellar masses of the components and more strongly on their radii (fifth power). The main objective of this work is to make available grids of evolutionary stellar models that, in addition to the traditional parameters (e.g. age, mass, logg, Teff), also contain the necessary parameters for the theoretical study of apsidal motion and tidal evolution. This information is useful for the study of the apsidal motion in eclipsing binaries and their tidal evolution, and can also be used for the same purpose in exoplanetary systems., All models were computed using the MESA package. We consider core overshooting for models with masses >=1.2M_{sun}_. For the amount of core overshooting adopted a recent relationship for mass times core overshooting. We adopted for the mixing-length parameter {alpha}_MLT_ the value 1.84 (the solar-calibrated value). Mass loss was taken into account in two evolutionary phases. The models were followed from the pre-main sequence phase to the white dwarf (WD) stage. The evolutionary models containing age, luminosity, logg, and Teff, as well as the first three harmonics of the internal stellar structure (k_2_, k_3_, and k_4_), the radius of gyration {beta} y, and the dimensionless variable {alpha}, related to gravitational potential energy, are presented in 69 tables covering three chemical compositions: [Fe/H] = -0.50, 0.00, and 0.50. Additional models with different input physics are available., Financial support from the Severo Ochoa grant CEX2021-001131-S funded by MCIN/AEI/ 10.13039/501100011033, No