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For the last three years, we have been following all southern supernovae brighter than V=15 in BVRIJHK with the YALO 1m telescope. To date we have followed 13 supernovae. We have published (or have preprints) the analysis of 4 supernovae. In the next semester we should have enough data to make our first attempt at a Hubble diagram based on infrared light curves of Type Ia supernovae. For this semester we are asking to continue the program on the YALO telescope in UBVIJHK, supplemented by one night per month on the 0.9m to measure local standards in the optical. We are also asking for a small amount of time on HET to get queue scheduled spectra of the equatorial supernovae which we need for EPM analysis of Type II supernovae or spectral classification for the Type Ia.

We present UBVRIz light curves of the Type Ia SN 1999ee and the Type Ib/c SN 1999ex, both located in the galaxy IC 5179. SN 1999ee has an extremely well-sampled light curve spanning from 10 days before Bmax through 53 days after peak. Near maximum, we find systematic differences of ~0.05 mag in photometry measured with two different telescopes, even though the photometry is reduced to the same local standards around the supernova using the specific color terms for each instrumental system. We use models for our bandpasses and spectrophotometry of SN 1999ee to derive magnitude corrections (S-corrections) and remedy this problem. This exercise demonstrates the need of accurately characterizing the instrumental system before great photometric accuracies of Type Ia supernovae can be claimed. It also shows that this effect can have important astrophysical consequences, since a small systematic shift of 0.02 mag in the B-V color can introduce a 0.08 mag error in the extinction-corrected peak B magnitude of a supernova and thus lead to biased cosmological parameters. The data for the Type Ib/c SN 1999ex present us with the first ever observed shock breakout of a supernova of this class. These observations show that shock breakout occurred 18 days before Bmax and support the idea that Type Ib/c supernovae are due to the core collapse of massive stars rather than thermonuclear disruption of white dwarfs.

We present UBVRIz lightcurves of the Type Ia SN 1999ee and the Type Ib/c SN 1999ex, both located in the galaxy IC 5179. SN 1999ee has an extremely well sampled lightcurve spanning from 10 days before Bmax through 53 days after peak. Near maximum we find systematic differences ~0.05 mag in photometry measured with two different telescopes, even though the photometry is reduced to the same local standards around the supernova using the specific color terms for each instrumental system. We use models for our bandpasses and spectrophotometry of SN 1999ee to derive magnitude corrections (S-corrections) and remedy this problem. This exercise demonstrates the need of accurately characterizing the instrumental system before great photometric accuracies of Type Ia supernovae can be claimed. It also shows that this effect can have important astrophysical consequences since a small systematic shift of 0.02 mag in the B-V color can introduce a 0.08 mag error in the extinction corrected peak B magnitudes of a supernova and thus lead to biased cosmological parameters. The data for the Type Ib/c SN 1999ex present us with the first ever observed shock breakout of a supernova of this class. These observations show that shock breakout occurred 18 days before Bmax and support the idea that Type Ib/c supernovae are due to core collapse of massive stars rather than thermonuclear disruption of white dwarfs.

We present well sampled optical (UBVRI) and infrared (JHK) light curves of the nearby (~18.0 Mpc) Type Ia supernova SN 2001el, from 11 days before to 142 days after the time of B-band maximum. The data represent one of the best sets of optical and infrared photometry ever obtained for a Type Ia supernova. Based on synthetic photometry using optical spectra of SN 2001el and optical and infrared spectra of SN 1999ee, we were able to devise filter corrections for the BVJHK photometry of SN 2001el which to some extent resolve systematic differences between SN 2001el datasets obtained with different telescope/filter/instrument combinations. We also calculated V minus infrared color curves on the basis of a delayed detonation model and showed that the theoretical color curves match the unreddened loci for Type Ia SNe with mid-range decline rates to within 0.2 mag. Given the completeness of the light curves and the elimination of filter-oriented systematic errors to some degree, the data presented here will be useful for the construction of photometric templates, especially in the infrared. On the whole the photometric behavior of SN 2001el was quite normal. The second H-band maximum being brighter than the first H-band maximum is in accord with the prediction of Krisciunas et al. (2000) for Type Ia SNe with mid-range decline rates. The photometry exhibits non-zero host extinction, with total A_V = 0.57 +/- 0.05 mag along the line of sight. NGC 1448, the host of SN 2001el, would be an excellent target for a distance determination using Cepheids.

In this project we created an atlas of near-infrared and optical light curves taken from the literature and from our unpublished JHK data of nearby SNe observed at CTIO and LCO. Our objective was to determine whether or not Type Ia supernovae are standardizable candles in the near-infrared. The preliminary conclusions are: a) The morphology of the infrared light curves does not form a simple monotonically changing sequence when organized as a function of evolutionary speed (Δ m15(B)). Apparently a few SNe which are otherwise normal in the optical seem to have anomalous near-infrared light curves, especially in the J-band. This makes it difficult to construct a single-parameter family of templates that characterize the infrared light curves. However, in general there is a pattern to the these light curves in the sense that the secondary maximum occurs later and more strongly for slower-declining SNe. But, as shown in Krisciunas et al. (2001) for the I-band, there are exceptions to this trend. b) H-band absolute magnitudes 10 days after the time of B-band maximum are essentially constant at -17.91 and not a function of Δ m15(B). c) We obtain a Hubble constant of 71.4 +/- 2.5 km s-1 Mpc-1 and a dispersion of +/-0.24 mag in the H-band Hubble diagram. 1CTIO REU/PIA student 2002.

This paper provides a progress report on a collaborative program at the Las Campanas and Cerro Tololo Observatories to observe the near-IR light curves of Type Ia supernovae. We discuss how the morphologies of the JHK light curves change as a function of the decline rate parameter \(\Delta\) m15(B). Evidence is presented which indicates that the absolute magnitudes in the H band have little or no dependence on the decline rate, suggesting that SNe Ia may be nearly perfect cosmological standard candles in the near-IR. A preliminary Hubble diagram in the H band is presented and compared with a similar diagram in V for the same objects. Finally, observations of two peculiar supernovae, 1999ac and 2001ay, are briefly discussed.

We present optical and infrared photometry of the unusual Type Ia supernova 2000cx. With the data of Li et al. (2001) and Jha (2002), this comprises the largest dataset ever assembled for a Type Ia SN, more than 600 points in UBVRIJHK. We confirm the finding of Li et al. regarding the unusually blue B-V colors as SN 2000cx entered the nebular phase. Its I-band secondary hump was extremely weak given its B-band decline rate. The V minus near infrared colors likewise do not match loci based on other slowly declining Type Ia SNe, though V-K is the least ``abnormal''. In several ways SN 2000cx resembles other slow decliners, given its B-band decline rate (Delta m_15(B) = 0.93), the appearance of Fe III lines and weakness of Si II in its pre-maximum spectrum, the V-K colors and post-maximum V-H colors. If the distance modulus derived from Surface Brightness Fluctuations of the host galaxy is correct, we find that the rate of light increase prior to maximum, the characteristics of the bolometric light curve, and the implied absolute magnitude at maximum are all consistent with a sub-luminous object with Delta m_15(B) ~ 1.6-1.7 having a higher than normal kinetic energy.

We present the summary results from the now completed Nearby Galaxies Supernova Search (NGSS) campaigns. These campaigns were conducted at KPNO 0.9-meter using the 8K x 8K MOSAIC camera. The wide-field provided by the camera (59\arcmin x 59\arcmin) allowed us to search nearly 750 square degrees of sky along the celestial equator for SNe, to a limiting magnitude of R ~21. Using search algorithms similar to those used by the High-z Supernova Search Team and the Supernova Cosmology Project for their campaigns, we have processed over 1.25 TB (1250 GB) of Mosaic imager data in real time to discover a sample of 42 SNe of various types and ages. With facilities at CTIO and other target of opportunity observations, we have photometrically followed many of these SNe and obtained very well sampled light curves. We present a detailed description of our 3 year project, search techniques, light curves of several of our SNe, and preliminary rates.