Temporal changes of the flare activity of Proxima Cen

We study temporal variations of the emission lines of Halpha, Hepsilon, H and K Ca II, D1 and D2 Na I, 4026 and 5876 A He I in the HARPS spectra of Proxima Centauri across an extended time of 13.2 years, from May 27, 2004, to September 30, 2017. Aims. We analyse the common behaviour and differences in the intensities and profiles of different emission lines in flare and quiet modes of Proxima activity. Methods. We compare the pseudo-equivalent widths (pEW) and profiles of the emission lines in the HARPS high-resolution (R ~ 115,000) spectra observed at the same epochs. Results. All emission lines show variability with a timescale of at least 10 min. The strength of all lines except He I 4026 A correlate with \Halpha. During strong flares the `red asymmetry' appears in the Halpha emission line indicating the infall of hot condensed matter into the chromosphere with velocities greater than 100 km/s disturbing chromospheric layers. As a result, the strength of the Ca II lines anti-correlates with Halpha during strong flares. The He I lines at 4026 and 5876 A appear in the strong flares. The cores of D1 and D2 Na I lines are also seen in emission. During the minimum activity of Proxima Centauri, Ca II lines and Hepsilon almost disappear while the blue part of the Na I emission lines is affected by the absorption in the extending and condensing flows. Conclusions. We see different behaviour of emission lines formed in the flare regions and chromosphere. Chromosphere layers of Proxima Cen are likely heated by the flare events; these layers are cooled in the `non-flare' mode. The self-absorption structures in cores of our emission lines vary with time due to the presence of a complicated system of inward and outward matter flows in the absorbing layers.Comment: 22 pages, 12 Figures, accepted by A

A-DInSAR Monitoring of Landslide and Subsidence Activity: A Case of Urban Damage in Arcos de la Frontera, Spain

Terrain surface displacements at a site can be induced by more than one geological process. In this work, we use advanced differential interferometry SAR (A-DInSAR) to measure ground deformation in Arcos de la Frontera (SW Spain), where severe damages related to landslide activity and subsidence have occurred in recent years. The damages are concentrated in two residential neighborhoods constructed between 2001 and 2006. One of the neighborhoods, called La Verbena, is located at the head of an active retrogressive landslide that has an extension of around 0.17 × 106 m2 and developed in weathered clayey soils. Landslide motion has caused building deterioration since they were constructed. After a heavy rainfall period in winter 2009–2010, the movement was accelerated, worsening the situation. The other neighborhood, Pueblos Blancos, was built over a poorly compacted artificial filling undergoing a spatially variable consolidation process which has also led to severe damage to buildings. For both cases, a short set of C-band data from the “ENVISAT 2010+” project has been used to monitor surface displacement for the period spanning April 2011–January 2012. In this work we characterize the mechanism of both ground deformation processes using in situ and remote sensing techniques along with a detailed geological interpretation and urban damage distribution

A search for substellar members in the Praesepe and sigma Orionis clusters

(Abridged). We have conducted deep photometric searches for substellar members of the Praesepe (0.5-1 Gyr) and sigma Orionis (3 Myr) star clusters using the Sloan i' and z' filters, the 3.5-m and the 5-m Hale telescopes on the Calar Alto and Palomar Observatories, respectively. The total area surveyed was 1177 arcmin^2 (Praesepe) and 1122 arcmin^2 (sigma Orionis) down to 5-sigma detection limits of i'= 24.5 and z'= 24 mag, corresponding to masses of 50-55 M_Jup (Praesepe) and 6 M_Jup (sigma Orionis). Besides recovering previously known cluster members reported in the literature, we have identified new photometric candidates in both clusters whose masses expand the full range covered by our study. In sigma Orionis, follow-up NIR photometry has allowed us to confirm the likely cluster membership of three newly discovered planetary-mass objects. The substellar mass function of sigma Orionis, which is complete from the star-brown dwarf borderline down to 7 M_Jup, keeps rising smoothly with a slope of alpha = 0.6^{+0.5}_{-0.1}. Very interestingly, one of the faintest Praesepe candidates for which we have also obtained follow-up JHK photometry nicely fits the expected optical and infrared photometric sequence of the cluster. From its colors, we have estimated its spectral type in the L4-L6 range. If confirmed as a true Praesepe member, it would become the first L-type brown dwarf (50-60 M_Jup) identified in an intermediate-age star cluster. Our derivation of the Praesepe mass function depends strongly on the cluster age. For the youngest possible ages (500-700 Myr), our results suggest that there is a deficit of Praesepe brown dwarfs in the central regions of the cluster, while the similarity between the Praesepe and sigma Orionis mass functions increases qualitatively for models older than 800 Myr.Comment: Accepted for publication in A&A. Figures 1, 7, and 9-12 are available in jpeg forma

Twenty-year advanced DInSAR analysis of severe land subsidence: The Alto Guadalentin Basin (Spain) case study

A twenty-year period of severe land subsidence evolution in the Alto Guadalentin Basin (southeast Spain) is monitored using multi-sensor SAR images, processed by advanced differential interferometric synthetic aperture radar (DInSAR) techniques. The SAR images used in this study consist of four datasets acquired by ERS-1/2, ENVISAT, ALOS and COSMO-SkyMed satellites between 1992 and 2012. The integration of ground surface displacement maps retrieved for different time periods allows us to quantify up to 2.50 m of cumulated displacements that occurred between 1992 and 2012 in the Alto Guadalentin Basin. DInSAR results were locally compared with global positioning system (GPS) data available for two continuous stations located in the study area, demonstrating the high consistency of local vertical motion measurements between the two different surveying techniques. An average absolute error of 4.6 +/- 4 mm for the ALOS data and of 4.8 +/- 3.5 mm for the COSMO-SkyMed data confirmed the reliability of the analysis. The spatial analysis of DInSAR ground surface displacement reveals a direct correlation with the thickness of the compressible alluvial deposits. Detected ground subsidence in the past 20 years is most likely a consequence of a 100-200 m groundwater level drop that has persisted since the 1970s due to the overexploitation of the Alto Guadalentin aquifer system. The negative gradient of the pore pressure is responsible for the extremely slow consolidation of a very thick (> 100 m) layer of fine-grained silt and clay layers with low vertical hydraulic permeability (approximately 50 mm/h) wherein the maximum settlement has still not been reached. (C) 2015 Published by Elsevier B.V

Expected Performance of the ATLAS Experiment - Detector, Trigger and Physics

A detailed study is presented of the expected performance of the ATLAS detector. The reconstruction of tracks, leptons, photons, missing energy and jets is investigated, together with the performance of b-tagging and the trigger. The physics potential for a variety of interesting physics processes, within the Standard Model and beyond, is examined. The study comprises a series of notes based on simulations of the detector and physics processes, with particular emphasis given to the data expected from the first years of operation of the LHC at CERN

Performance of the CMS Cathode Strip Chambers with Cosmic Rays

The Cathode Strip Chambers (CSCs) constitute the primary muon tracking device in the CMS endcaps. Their performance has been evaluated using data taken during a cosmic ray run in fall 2008. Measured noise levels are low, with the number of noisy channels well below 1%. Coordinate resolution was measured for all types of chambers, and fall in the range 47 microns to 243 microns. The efficiencies for local charged track triggers, for hit and for segments reconstruction were measured, and are above 99%. The timing resolution per layer is approximately 5 ns

An ultra-short-period transiting super-Earth orbiting the M3 dwarf TOI-1685

Funding: We acknowledge financial support from the Agencia Estatal de Investigación of the Ministerio de Ciencia, Innovación y Universidades and the ERDF through projects PID2019-109522GB-C5[1:4]/AEI/10.13039/501100011033, PGC2018-098153-B-C33, and the Centre of Excellence “Severo Ochoa” and “María deMaeztu” awards to the Instituto de Astrofísica de Canarias (SEV-2015-0548), Instituto de Astrofísica de Andalucía (SEV-2017-0709), and Centro de Astro-biología (MDM-2017-0737), the Generalitat de Catalunya/CERCA programme,“la Caixa” Foundation (100010434), European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No. 847648 (LCF/BQ/PI20/11760023), a University Research Support Grant from the National Astronomical Observatory of Japan, JSPS KAKENHI (JP15H02063, JP18H01265, JP18H05439, JP18H05442, and JP22000005), JSTPRESTO (JPMJPR1775), UK Science and Technology Facilities Council (ST/R000824/1), and NASA (NNX17AG24G).Dynamical histories of planetary systems, as well as the atmospheric evolution of highly irradiated planets, can be studied by characterizing the ultra-short-period planet population, which the TESS mission is particularly well suited to discover. Here, we report on the follow-up of a transit signal detected in the TESS sector 19 photometric time series of the M3.0 V star TOI-1685 (2MASS J04342248+4302148). We confirm the planetary nature of the transit signal, which has a period of Pb = 0.6691403−0.0000021+0.0000023 d, using precise radial velocity measurements taken with the CARMENES spectrograph. From the joint photometry and radial velocity analysis, we estimate the following parameters for TOI-1685 b: a mass of Mb = 3.78−0.63+0.63 M⊕, a radius of Rb = 1.70−0.07+0.07 R⊕, which together result in a bulk density of ρb = 4.21−0.82+0.95 g cm−3, and an equilibrium temperature of Teq = 1069−16+16 K. TOI-1685 b is the least dense ultra-short-period planet around an M dwarf known to date. TOI-1685 b is also one of the hottest transiting super-Earth planets with accurate dynamical mass measurements, which makes it a particularly attractive target for thermal emission spectroscopy. Additionally, we report with moderate evidence an additional non-transiting planet candidate in the system, TOI-1685 [c], which has an orbital period of Pc = 9.02−0.12+0.10 d.Publisher PDFPeer reviewe

Performance and Operation of the CMS Electromagnetic Calorimeter

The operation and general performance of the CMS electromagnetic calorimeter using cosmic-ray muons are described. These muons were recorded after the closure of the CMS detector in late 2008. The calorimeter is made of lead tungstate crystals and the overall status of the 75848 channels corresponding to the barrel and endcap detectors is reported. The stability of crucial operational parameters, such as high voltage, temperature and electronic noise, is summarised and the performance of the light monitoring system is presented

Gliese 49: activity evolution and detection of a super-Earth A HADES and CARMENES collaboration

Small planets around low-mass stars often show orbital periods in a range that corresponds to the temperate zones of their host stars which are therefore of prime interest for planet searches. Surface phenomena such as spots and faculae create periodic signals in radial velocities and in observational activity tracers in the same range, so they can mimic or hide true planetary signals. We aim to detect Doppler signals corresponding to planetary companions, determine their most probable orbital configurations, and understand the stellar activity and its impact on different datasets. We analyze 22 years of data of the M1.5V-type star Gl49 (BD+61 195) including HARPS-N and CARMENES spectrographs, complemented by APT2 and SNO photometry. Activity indices are calculated from the observed spectra, and all datasets are analyzed with periodograms and noise models. We investigate how the variation of stellar activity imprints on our datasets. We further test the origin of the signals and investigate phase shifts between the different sets. To search for the best-fit model we maximize the likelihood function in a Markov Chain Monte Carlo approach. As a result of this study, we are able to detect the super-Earth Gl49b with a minimum mass of 5.6 Ms. It orbits its host star with a period of 13.85d at a semi-major axis of 0.090 au and we calculate an equilibrium temperature of 350 K and a transit probability of 2.0%. The contribution from the spot-dominated host star to the different datasets is complex, and includes signals from the stellar rotation at 18.86d, evolutionary time-scales of activity phenomena at 40-80d, and a long-term variation of at least four years