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Abstract We present the second and final release of optical spectroscopy of Type Ia supernovae (SNe Ia) obtained during the first and second phases of the Carnegie Supernova Project (CSP-I and CSP-II). The newly released data consist of 148 spectra of 30 SNe Ia observed in the course of CSP-I and 234 spectra of 127 SNe Ia obtained during CSP-II. We also present 216 optical spectra of 46 historical SNe Ia, including 53 spectra of 30 SNe Ia observed by the Calán/Tololo Supernova Survey. We combine these observations with previously published CSP data and publicly available spectra to compile a large sample of measurements of spectroscopic parameters at maximum light, consisting of pseudo-equivalent widths and expansion velocities of selected features for 232 CSP and historical SNe Ia (including more than 1000 spectra). Finally, we review some of the strongest correlations between spectroscopic and photometric properties of SNe Ia. Specifically, we define two samples: one consisting of SNe Ia discovered by targeted searches (most of them CSP-I objects) and the other composed of SNe Ia discovered by untargeted searches, which includes most of the CSP-II objects. The analyzed correlations are similar for both samples. We find a larger incidence of SNe Ia belonging to the cool and broad-line Branch subtypes among the events discovered by targeted searches, shallow-silicon SNe Ia are present with similar frequencies in both samples, while core normal SNe Ia are more frequent in untargeted searches. 

Abstract We present a spectroscopic survey of 248 white dwarf candidates within 40 pc of the Sun; of these 244 are in the Southern hemisphere. Observations were performed mostly with the Very Large Telescope (X-Shooter) and Southern Astrophysical Research Telescope. Almost all candidates were selected from Gaia Data Release 3 (DR3). We find a total of 246 confirmed white dwarfs, 209 of which had no previously published spectra, and two main-sequence star contaminants. Of these, 100 white dwarfs display hydrogen Balmer lines, 69 have featureless spectra, and two show only neutral helium lines. Additionally, 14 white dwarfs display traces of carbon, while 37 have traces of other elements that are heavier than helium. We observe 35 magnetic white dwarfs through the detection of Zeeman splitting of their hydrogen Balmer or metal spectral lines. High spectroscopic completeness (> 97 per cent) has now been reached, such that we have 1058 confirmed Gaia DR3 white dwarfs out of 1083 candidates within 40 pc of the Sun at all declinations. 

Abstract We present optical and near-infrared photometric and spectroscopic observations of the fast-declining Type Ia supernova (SN) 2015bo. SN 2015bo is underluminous (M_B= −17.50 ± 0.15 mag) and has a fast-evolving light curve (Δm15(B) = 1.91 ± 0.01 mag ands_BV= 0.48 ± 0.01). It has a unique morphology in the observedV−rcolor curve, where it is bluer than all other supernovae (SNe) in the comparison sample. A⁵⁶Ni mass of 0.17 ± 0.03M_⊙was derived from the peak bolometric luminosity, which is consistent with its location on the luminosity–width relation. Spectroscopically, SN 2015bo is a cool SN in the Branch classification scheme. The velocity evolution measured from spectral features is consistent with 1991bg-like SNe. SN 2015bo has a SN twin (similar spectra)andsibling (same host galaxy), SN 1997cn. Distance moduli ofμ= 34.33 ± 0.01 (stat) ±0.11 (sys) mag andμ= 34.34 ± 0.04 (stat) ± 0.12 (sys) mag are derived for SN 2015bo and SN 1997cn, respectively. These distances are consistent at the 0.06σlevel with each other, and they are also consistent with distances derived using surface-brightness fluctuations and redshift-corrected cosmology. This suggests that fast-declining SNe could be accurate distance indicators, which should not be excluded from future cosmological analyses.