We present new optical and near‐infrared (NIR) photometry and spectroscopy of the Type IIP supernova (SN), SN 2004et. In combination with already published data, this provides one of the most complete studies of optical and NIR data for any Type IIP SN from just after explosion to +500 d. The contribution of the NIR flux to the bolometric light curve is estimated to increase from 15 per cent at explosion to around 50 per cent at the end of the plateau and then declines to 40 per cent at 300 d. SN 2004et is one of the most luminous IIP SNe which has been well studied and characterized, and with a luminosity of log L= 42.3 erg s−1 and a 56Ni mass of 0.06 ± 0.04 M⊙, it is two times brighter than SN 1999em. We provide parametrized bolometric corrections as a function of time since explosion for SN 2004et and three other IIP SNe that have extensive optical and NIR data. These can be used as templates for future events in optical and NIR surveys without full wavelength coverage. We compare the physical parameters of SN 2004et with those of other well‐studied IIP SNe and find that the kinetic energies span a range of 1050–1051 erg. We compare the ejected masses calculated from hydrodynamic models with the progenitor masses and limits derived from pre‐discovery images. Some of the ejected mass estimates are significantly higher than the progenitor mass estimates, with SN 2004et showing perhaps the most serious mass discrepancy. With the current models, it appears difficult to reconcile 100 d plateau lengths and high expansion velocities with the low ejected masses of 5–6 M⊙ implied from 7–8 M⊙ progenitors. The nebular phase is studied using very late‐time Hubble Space Telescope photometry, along with optical and NIR spectroscopy. The light curve shows a clear flattening at 600 d in the optical and the NIR, which is likely due to the ejecta impacting on circumstellar material. We further show that the [O i] 6300, 6364 Å line strengths in the nebular spectra of four Type IIP SNe imply ejected oxygen masses of 0.5–1.5 M⊙.

We present photometric and spectroscopic observations at optical and near-infrared wavelengths of the nearby type Ic supernova 2007gr. These represent the most extensive data-set to date of any supernova of this sub-type, with frequent coverage from shortly after discovery to more than one year post-explosion. We deduce a rise time to B-band maximum of 11.5 ± 2.7 d. We find a peak B-band magnitude of M B = −16.8, and light curves which are remarkably similar to the so-called "hypernova" SN 2002ap. In contrast, the spectra of SNe 2007gr and 2002ap show marked differences, not least in their respective expansion velocities. We attribute these differences primarily to the density profiles of their progenitor stars at the time of explosion i.e. a more compact star for SN 2007gr compared to SN 2002ap. From the quasi-bolometric light curve of SN 2007gr, we estimate that 0.076 ± 0.010 M of 56 Ni was produced in the explosion. Our near-infrared (IR) spectra clearly show the onset and disappearance of the first overtone of carbon monoxide (CO) between ∼70 to 175 d relative to B-band maximum. The detection of the CO molecule implies that ionised He was not microscopically mixed within the carbon/oxygen layers. From the optical spectra, near-IR light curves, and colour evolution, we find no evidence for dust condensation in the ejecta out to about +400 d. Given the combination of unprecedented temporal coverage, and high signal-to-noise data, we suggest that SN 2007gr could be used as a template object for supernovae of this sub-class.

We present Hubble Space Telescope VI photometry of the central region of the Large Magellanic Cloud cluster NGC 1866, reaching magnitudes as faint as V = 27. We find evidence that the cluster luminosity function shows a strong dependence on the distance from the cluster center, with a clear deficiency of lowluminosity stars in the inner region. We discuss a global cluster luminosity function as obtained from stars from all parts of the investigated region, which appears in impressive agreement with the prediction from a Salpeter mass distribution. We also revisit the use of NGC 1866 as a probe for determining the efficiency of core overshooting and conclude that a definitive answer to this question is not possible from this cluster.

We present a new complete Near-Infrared (NIR, JHK s ) census of RR Lyrae stars (RRLs) in the globular ω Cen (NGC 5139). We collected 15,472 JHK s images with 4-8m class telescopes over 15 years (2000)(2001)(2002)(2003)(2004)(2005)(2006)(2007)(2008)(2009)(2010)(2011)(2012)(2013)(2014)(2015) covering a sky area around the cluster center of 60×34 arcmin 2 . These images provided calibrated photometry for 182 out of the 198 cluster RRL candidates with ten to sixty measurements per band. We also provide new homogeneous estimates of the photometric amplitude for 180 (J), 176 (H) and 174 (K s ) RRLs. These data were supplemented with single-epoch JK s magnitudes from VHS and with single-epoch H magnitudes from 2MASS. Using proprietary optical and NIR data together with new optical light curves (ASAS-SN) we also updated pulsation periods for 59 candidate RRLs. As a whole, we provide JHK s magnitudes for 90 RRab (fundamentals), 103 RRc (first overtones) and one RRd (mixed-mode pulsator). We found that NIR/optical photometric amplitude ratios increase when moving from first overtone to fundamental and to long-period (P>0.7 days) fundamental RRLs. Using predicted Period-Luminosity-Metallicity relations, we derive a true distance modulus of 13.674±0.008±0.038 mag (statistical error and standard deviation of the median)-based a This publication makes use of data gathered with the Magellan/Baade Telescope at Las Campanas Observatory, the Blanco Telescope at Cerro Tololo Inter-American Observatory, NTT at La Silla (ESO Program IDs: 64.N-0038(A), 66.D-0557(A), 68.D-0545(A), 073.D-0313(A), ID 073.D-0313(A) and 59.A-9004(D)), VISTA at Paranal (ESO Program ID: 179.A-2010) and VLT at Paranal (ESO Program ID: ID96406).RRc RRab Global DM err a σ b DM err a σ b DM err a σ b mag mag mag mag mag mag mag mag mag -[Fe/H] from Sollima et al. (2006a)--Theoretical calibration-J 13.658 0.009 0.047 13.656 0.012 0.029 13.655 0.009 0.035 H 13.675 0.006 0.044 13.676 0.008 0.034 13.674 0.006 0.033 K s 13.697 0.005 0.041 13.687 0.007 0.026 13.690 0.005 0.029 mean JHKs 13.677 0.007 0.047 13.673 0.009 0.032 13.673 0.007 0.036 Overall mean: 13.674±0.008±0.038 -Empirical calibration-J 13.693 0.016 0.027 13.809 0.017 0.062 13.755 0.011 0.031 H 13.666 0.015 0.032 13.791 0.017 0.032 13.766 0.010 0.031 K s 13.707 0.015 0.034 13.819 0.017 0.025 13.772 0.010 0.029 mean JHKs 13.689 0.015 0.035 13.806 0.017 0.045 13.764 0.010 0.031 Overall mean: 13.757±0.014±0.056 -[Fe/H] from Braga et al. (2016)--Theoretical calibration-J 13.681 0.005 0.045 13.677 0.006 0.036 13.675 0.004 0.048 H 13.694 0.004 0.041 13.706 0.005 0.041 13.699 0.003 0.045 K s 13.723 0.003 0.045 13.713 0.005 0.037 13.720 0.003 0.051 mean JHKs 13.699 0.004 0.047 13.699 0.005 0.041 13.698 0.004 0.052 Overall mean: 13.698±0.004±0.048 -Empirical calibration-J 13.725 0.009 0.031 13.853 0.012 0.034 13.767 0.006 0.036 H 13.691 0.008 0.030 13.819 0.011 0.036 13.772 0.005 0.037 K s 13.742 0.008 0.032 13.839 0.011 0.037 13.791 0.005 0.039 mean JHKs 13.719 0.008 0.037 13.837 0.012 0.038 13.777 0.005 0.039Ove...

Abstract. We present WFPC2 photometry of 21 stellar clusters of the Large Magellanic Cloud obtained on images retrieved from the Hubble Space Telescope archive. The derived colour magnitude diagrams (CMDs) are presented and discussed. This database provides a sample of CMDs representing, with reliable statistics, simple stellar populations with a large spread of age. The stars in the core of the clusters are all resolved and measured at least down to the completeness limit; the magnitudes of the main sequence terminations and of the red giant clump are also evaluated for each cluster, together with the radius at half maximum of the star density.