Rubin-LSST

Abstract:

A search for dijet resonances in events with at least one isolated charged lepon is performed using 139 fb−1 of s = 13 TeV proton-proton collision data recorded by the ATLAS detector at the LHC. The dijet invariant-mass (mjj) distribution constructed from events with at least one isolated electron or muon is searched in the region 0.22 < mjj< 6.3 TeV for excesses above a smoothly falling background from Standard Model processes. Triggering based on the presence of a lepton in the event reduces limitations imposed by minimum transverse momentum thresholds for triggering on jets. This approach allows smaller dijet invariant masses to be probed than in inclusive dijet searches, targeting a variety of new-physics models, for example ones in which a new state is produced in association with a leptonically decaying W or Z boson. No statistically significant deviation from the Standard Model background hypothesis is found. Limits on contributions from generic Gaussian signals with widths ranging from that determined by the detector resolution up to 15% of the resonance mass are obtained for dijet invariant masses ranging from 0.25 TeV to 6 TeV. Limits are set also in the context of several scenarios beyond the Standard Model, such as the Sequential Standard Model, a technicolor model, a charged Higgs boson model and a simplified Dark Matter model.

Abstract:

This paper documents the 16th data release (DR16) from the Sloan Digital Sky Surveys (SDSS), the fourth and penultimate from the fourth phase (SDSS-IV). This is the first release of data from the Southern Hemisphere survey of the Apache Point Observatory Galactic Evolution Experiment 2 (APOGEE-2); new data from APOGEE-2 North are also included. DR16 is also notable as the final data release for the main cosmological program of the Extended Baryon Oscillation Spectroscopic Survey (eBOSS), and all raw and reduced spectra from that project are released here. DR16 also includes all the data from the Time Domain Spectroscopic Survey and new data from the SPectroscopic IDentification of ERosita Survey programs, both of which were co-observed on eBOSS plates. DR16 has no new data from the Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) survey (or the MaNGA Stellar Library "MaStar"). We also preview future SDSS-V operations (due to start in 2020), and summarize plans for the final SDSS-IV data release (DR17).

Abstract:

Core-collapse supernovae (CCSNe) are the bright explosions of massive stars. During the explosion heavy elements are produced by nuclear burning. One of these products is 56Ni that radioactively decays into 56Co. The explosion energy and the produced 56Ni and its product 56Co are what powers the light curves of classical supernovae (SNe). Stripped envelope (SE) SNe have lost their hydrogen (H) and in some cases, helium (He) envelopes through mass loss at some point in their lives. These SE SNe are known to produce SNe of types IIb (weak H), Ib (He-rich), Ic (He-poor), and Ic-BL (He-poor broad lines). Type IIn SNe, on the other hand, are SNe that interact with circumstellar medium (CSM) around the progenitor. The CSM is thought to be caused by the progenitor’s mass loss. The mechanism of the mass loss for these can happen in a variety of ways. All stars have mass loss through stellar winds, but in some cases, it is not enough to produce interaction that would produce a type IIn. The mass loss can also happen because of pair instability pulsations, eruptions, or binary effects. The mass loss can be studied by analysing the observational properties of a SN and understanding the mass loss might shed light on what kind of progenitor produced the SN. In this thesis, photometric and spectroscopic data of SN 2017dio are analysed. The photometric data are used to study the explosion epoch, light curves, and color curves of SN 2017dio and it is compared with four other SNe. The spectroscopic data are used to verify the classification of SN 2017dio, to study the spectral evolution, and to discuss the possible CSM properties and progenitor scenario. The findings indicate that SN 2017dio is a SN of type Ic-BL interacting with H-rich CSM. Both spectroscopic and photometric analysis support the theory of the CSM not being close to the explosion site and the calculated mass loss rate 0.04M⊙/year indicates that the progenitor must have experienced massive mass loss periods in the decade before its explosion