Peter Challis

Stellar Locus Regression: Accurate Color Calibration, and the Real-time Determination of Galaxy Cluster Photometric Redshifts (2009)

High, F. William, Stubbs, Christopher W., Rest, Armin, Stalder, Brian, Challis, Peter

We present Stellar Locus Regression (SLR), a method of directly adjusting the instrumental broadband optical colors of stars to bring them into accord with a universal stellar color-color locus,...

CfA3: 185 Type Ia Supernova Light Curves from the CfA (2009)

Hicken, Malcolm, Challis, Peter, Jha, Saurabh, Kirshner, Robert P., Matheson, Tom, Modjaz, Maryam, ...

We present multi-band photometry of 185 type-Ia supernovae (SN Ia), with over 11500 observations. These were acquired between 2001 and 2008 at the F. L. Whipple Observatory of the Harvard-Smithsonian...

Improved Dark Energy Constraints from ~100 New CfA Supernova Type Ia Light Curves (2009)

Hicken, Malcolm, Wood-Vasey, W. Michael, Blondin, Stephane, Challis, Peter, Jha, Saurabh, Kelly, Patrick L., ...

We combine the CfA3 supernova Type Ia (SN Ia) sample with samples from the literature to calculate improved constraints on the dark energy equation of state parameter, w. The CfA3 sample is added to...

Time evolution of the line emission from the inner circumstellar ring of SN 1987A and its hot spots (2008)

Groeningsson, Per, Fransson, Claes, Leibundgut, Bruno, Lundqvist, Peter, Challis, Peter, Chevalier, Roger A., ...

We present seven epochs between October 1999 and November 2007 of high resolution VLT/UVES echelle spectra of the ejecta-ring collision of SN 1987A. The fluxes of most of the narrow lines from the...

Late-Time HST Photometry of SN 1994I: Hints of Positron Annihilation Energy Deposition (2008)

Clocchiatti, Alejandro, Wheeler, J. Craig, Kirshner, Robert P., Branch, David, Challis, Peter, Chevalier, Roger A., ...

We present multicolor Hubble Space Telescope (HST) WFPC2 broadband observations of the Type Ic SN 1994I obtained approximately 280 days after maximum light. We measure the brightness of the SN and,...

Improved cosmological constraints from new, old, and combined supernova data sets (2008)

Kowalski, M., Rubin, D., Aldering, G., Agostinho, R. J., Amadon, A., Amanullah, R., ...

We present a new compilation of Type Ia supernovae (SNe Ia), a new data set of low-redshift nearby-Hubble-flow SNe, and new analysis procedures to work with these heterogeneous compilations. This...

Improved cosmological constraints from new, old, and combined supernova data sets (2008)

Kowalski, M., Rubin, D., Aldering, G., Agostinho, R. J., Amadon, A., Amanullah, R., ...

We present a new compilation of Type Ia supernovae (SNe Ia), a new data set of low-redshift nearby-Hubble-flow SNe, and new analysis procedures to work with these heterogeneous compilations. This...

1999. The American Astronomical Society. All rights reserved. Printed in U.S.A. ( THE TYPE Ia SUPERNOVA 1998bu IN M96 AND THE HUBBLE CONSTANT (2007)

Saurabh Jha, Peter M. Garnavich, Robert P. Kirshner, Peter Challis, Alicia M. Soderberg, Lucas M. Macri, ...

We present optical and near-infrared photometry and spectroscopy of the Type Ia SN 1998bu in the Leo I Group galaxy M96 (NGC 3368). The data set consists of 356 photometric measurements and 29...

Type Ia Supernovae are Good Standard Candles in the Near Infrared: Evidence from PAIRITEL (2007)

Wood-Vasey, W. Michael, Friedman, Andrew S., Bloom, Joshua S., Hicken, Malcolm, Modjaz, Maryam, Kirshner, Robert P., ...

We have obtained 1087 NIR (JHKs) measurements of 21 SNe Ia using PAIRITEL, nearly doubling the number of well-sampled NIR SN Ia light curves. These data strengthen the evidence that SNe Ia are...

Lightcurves of Type Ia Supernovae from Near the Time of Explosion (2006)

Garg, Arti, Stubbs, Christopher W., Challis, Peter, Wood-Vasey, W. Michael, Blondin, Stephane, Huber, Mark E., ...

We present a set of 11 type Ia supernova (SN Ia) lightcurves with dense, pre-maximum sampling. These supernovae (SNe), in galaxies behind the Large Magellanic Cloud (LMC), were discovered by the...

SN 1987A After 18 Years: Mid-Infrared GEMINI and SPITZER Observations of the Remnant (2006)

Bouchet, Patrice, Dwek, Eli, Danziger, I. John, Arendt, Richard G., Park, Sangwook, ...

We present high resolution 11.7 and 18.3um mid-IR images of SN 1987A obtained on day 6526 with T-ReCS attached to the Gemini telescope. The 11.7um flux has increased significantly since our last...

Using Line Profiles to Test the Fraternity of Type Ia Supernovae at High and Low Redshifts (2006)

Blondin, Stéphane, Dessart, Luc, Leibundgut, Bruno, Branch, David, Höflich, Peter, Tonry, John L., ...

Using archival data of low-redshift (z < 0.01; Center for Astrophysics and SUSPECT databases) Type Ia supernovae (SNe Ia) and recent observations of high-redshift (0.16 < z < 0.64) SNe Ia, we study...

Using Line Profiles to Test the Fraternity of Type Ia Supernovae at High and Low Redshifts (2006)

Blondin, Stéphane, Dessart, Luc, Leibundgut, Bruno, Branch, David, Höflich, Peter, Tonry, John L., ...

Using archival data of low-redshift (z < 0.01; Center for Astrophysics and SUSPECT databases) Type Ia supernovae (SNe Ia) and recent observations of high-redshift (0.16 < z < 0.64) SNe Ia, we study...

Hubble Space Telescope and ground-based observations of type Ia supernovae at redshift 0.5: cosmological implications (2006)

Clocchiatti, Alejandro, Schmidt, Brian P., Filippenko, Alexei V., Challis, Peter, Coil, Alison L., Covarrubias, R., ...

We present observations of the Type I Supernovae (SNe) 1999M, 1999N, 1999Q, 1999S, and 1999U, at redshiftz z ≈ 0.5. They were discovered in early 1999 with the 4.0 m Blanco telescope at Cerro...

Hubble Space Telescope and ground-based observations of type Ia supernovae at redshift 0.5: cosmological implications (2006)

Clocchiatti, Alejandro, Schmidt, Brian P., Filippenko, Alexei V., Challis, Peter, Coil, Alison L., Covarrubias, R., ...

We present observations of the Type I Supernovae (SNe) 1999M, 1999N, 1999Q, 1999S, and 1999U, at redshiftz z ≈ 0.5. They were discovered in early 1999 with the 4.0 m Blanco telescope at Cerro...

UBVRI Light Curves of 44 Type Ia Supernovae (2005)

Jha, Saurabh, Kirshner, Robert P., Challis, Peter, Garnavich, Peter M., Matheson, Thomas

We present UBVRI photometry of 44 type-Ia supernovae (SN Ia) observed from 1997 to 2001 as part of a continuing monitoring campaign at the Fred Lawrence Whipple Observatory of the Harvard-Smithsonian...

Hubble Space Telescope Observations of Nine High-Redshift ESSENCE Supernovae (2005)

Krisciunas, Kevin, Garnavich, Peter M., Challis, Peter, Prieto, Jose Luis, Riess, A. G., Barris, B., ...

We present broad-band light curves of nine supernovae ranging in redshift from 0.5 to 0.8. The supernovae were discovered as part of the ESSENCE project, and the light curves are a combination of...

An Atlas of Spectrophotometric Landolt Standard Stars (2005)

Stritzinger, Maximilian, Suntzeff, Nicholas B., Hamuy, Mario, Challis, Peter, Demarco, Ricardo, Germany, Lisa, ...

We present CCD observations of 102 Landolt standard stars obtained with the R-C spectrograph on the CTIO 1.5 m telescope. Using stellar atmosphere models we have extended the flux points to our six...

An atlas of spectrophotometric landolt standard stars (2005)

Stritzinger, Maximilian, Suntzeff, Nicholas B., Hamuy, Mario, Challis, Peter, Demarco, Ricardo, Germany, Lisa M., ...

We present CCD observations of 102 Landolt standard stars obtained with the Ritchey-Chrétien spectrograph on the Cerro Tololo Inter-American Observatory 1.5 m telescope. Using stellar atmosphere...

An atlas of spectrophotometric landolt standard stars (2005)

Stritzinger, Maximilian, Suntzeff, Nicholas B., Hamuy, Mario, Challis, Peter, Demarco, Ricardo, Germany, Lisa M., ...

We present CCD observations of 102 Landolt standard stars obtained with the Ritchey-Chrétien spectrograph on the Cerro Tololo Inter-American Observatory 1.5 m telescope. Using stellar atmosphere...

An atlas of spectrophotometric landolt standard stars (2005)

Stritzinger, Maximilian, Suntzeff, Nicholas B., Hamuy, Mario, Challis, Peter, Demarco, Ricardo, Germany, Lisa M., ...

We present CCD observations of 102 Landolt standard stars obtained with the Ritchey-Chrétien spectrograph on the Cerro Tololo Inter-American Observatory 1.5 m telescope. Using stellar atmosphere...

An atlas of spectrophotometric landolt standard stars (2005)

Stritzinger, Maximilian, Suntzeff, Nicholas B., Hamuy, Mario, Challis, Peter, Demarco, Ricardo, Germany, Lisa M., ...

We present CCD observations of 102 Landolt standard stars obtained with the Ritchey-Chrétien spectrograph on the Cerro Tololo Inter-American Observatory 1.5 m telescope. Using stellar atmosphere...

An atlas of spectrophotometric landolt standard stars (2005)

Stritzinger, Maximilian, Suntzeff, Nicholas B., Hamuy, Mario, Challis, Peter, Demarco, Ricardo, Germany, Lisa M., ...

We present CCD observations of 102 Landolt standard stars obtained with the Ritchey-Chrétien spectrograph on the Cerro Tololo Inter-American Observatory 1.5 m telescope. Using stellar atmosphere...

The late-time light curve of the Type Ia supernova 2000cx (2004)

Sollerman, Jesper, Lindahl, Jan, Kozma, Cecilia, Challis, Peter, Filippenko, Alexei V., Fransson, Claes, ...

We have conducted a systematic and comprehensive monitoring programme of the Type Ia supernova 2000cx at late phases using the VLT and HST. The VLT observations cover phases 360 to 480 days past...

GRB 021211 as a Faint Analogue of GRB 990123: Exploring the Similarities and Differences in their Optical Afterglows (2004)

Holland, Stephen T., Bersier, David, Bloom, J. S., Garnavich, Peter G., Caldwell, Nelson, Challis, Peter, ...

We present B, V, Rc, J, H, and Ks photometry of the optical afterglow of the gamma-ray burst GRB 021211 taken at the Magellan, MMT, and WIYN observatories between 0.7 and 50 days after the burst. We...

Type Ia Supernova Discoveries at z>1 From the Hubble Space Telescope: Evidence for Past Deceleration and Constraints on Dark Energy Evolution (2004)

Riess, Adam G., Strolger, Louis-Gregory, Tonry, John, Casertano, Stefano, Ferguson, Henry C., Mobasher, Bahram, ...

We have discovered 16 Type Ia supernovae (SNe Ia) with the Hubble Space Telescope (HST) and have used them to provide the first conclusive evidence for cosmic deceleration that preceded the current...

23 High Redshift Supernovae from the IfA Deep Survey: Doubling the SN Sample at z>0.7 (2003)

Barris, Brian J., Tonry, John, Blondin, Stephane, Challis, Peter, Chornock, Ryan, Clocchiatti, Alejandro, ...

We present photometric and spectroscopic observations of 23 high redshift supernovae spanning a range of z=0.34-1.03, 9 of which are unambiguously classified as Type Ia. These supernovae were...

Imaging and Demography of the Host Galaxies of High-Redshift Type Ia Supernovae (2003)

Williams, Benjamin F., Hogan, Craig J., Barris, Brian, Candia, Pablo, Challis, Peter, Clocchiatti, Alejandro, ...

We present the results of a study of the host galaxies of high redshift Type Ia supernovae (SNe Ia). We provide a catalog of 18 hosts of SNe Ia observed with the Hubble Space Telescope (HST) by the...

Identification of Type Ia Supernovae at Redshift 1.3 and Beyond with the Advanced Camera for Surveys on HST (2003)

Riess, Adam G., Strolger, Louis-Gregory, Tonry, John, Tsvetanov, Zlatan, Casertano, Stefano, Ferguson, Henry C., ...

We present discoveries of SNe Ia at z > 1 and the photometric diagnostic used to discriminate them from other types of SNe detected during the GOODS Hubble Space Telescope Treasury program with the...

Cosmological Results from High-z Supernovae (2003)

Tonry, John L., Schmidt, Brian P., Barris, Brian, Candia, Pablo, Challis, Peter, Clocchiatti, Alejandro, ...

The High-z Supernova Search Team has discovered and observed 8 new supernovae in the redshift interval z=0.3-1.2. These independent observations, confirm the result of Riess et al. (1998a) and...

SN 2002cx: The Most Peculiar Known Type Ia Supernova (2003)

Li, Weidong, Filippenko, Alexei V., Chornock, Ryan, Berger, Edo, Berlind, Perry, Calkins, Michael L., ...

We present photometric and spectroscopic observations of supernova (SN) 2002cx, which reveal it to be unique among all observed type Ia supernovae (SNe Ia). SN 2002cx exhibits a SN 1991T-like...

The Luminosity of SN 1999by in NGC 2841 and the Nature of `Peculiar' Type Ia Supernovae (2001)

Garnavich, Peter M., Bonanos, Alceste Z., Krisciunas, Kevin, Jha, Saurabh, Kirshner, Robert P., Schlegel, Eric M., ...

We present UBVRIJHK photometry and optical spectroscopy of the so-called 'peculiar' Type Ia supernova 1999by in NGC 2841. The observations began one week before visual maximum light which is...

Optical Spectra of Type Ia Supernovae at z=0.46 and z=1.2 (2000)

Coil, Alison L., Matheson, Thomas, Filippenko, Alexei V., Leonard, Douglas C., Tonry, John, Riess, Adam G., ...

We present optical spectra, obtained with the Keck 10-m telescope, of two high-redshift type Ia supernovae (SNe Ia) discovered by the High-z Supernova Search Team: SN 1999ff at z=0.455 and SN 1999fv...

HST Spectroscopy of Spot 1 on the Circumstellar Ring of SN 1987A (2000)

Michael, Eli, McCray, Richard, Pun, C. S. J., Garnavich, Peter, Challis, Peter, Kirshner, Robert P., ...

We present ultraviolet and optical spectra of the first bright spot (PA = 29 degrees) on Supernova 1987A's equatorial circumstellar ring taken with the Space Telescope Imaging Spectrograph. We...

Tests of the Accelerating Universe with Near-Infrared Observations of a High-Redshift Type Ia Supernova (2000)

Riess, Adam G., Filippenko, Alexei V., Liu, Michael C., Challis, Peter, Clocchiatti, Alejandro, Diercks, Alan, ...

We have measured the rest-frame B,V, and I-band light curves of a high-redshift type Ia supernova (SN Ia), SN 1999Q (z=0.46), using HST and ground-based near-infrared detectors. A goal of this study...

Late-Time Optical and UV Spectra of SN 1979C and SN 1980K (1998)

Fesen, Robert A., Gerardy, Christopher L., Filippenko, Alexei V., Matheson, Thomas, Chevalier, Roger A., Kirshner, Robert P., ...

A low-dispersion Keck I spectrum of SN 1980K taken in August 1995 (t = 14.8 yr after explosion) and a November 1997 MDM spectrum (t = 17.0 yr) show broad 5500 km s^{-1} emission lines of H\alpha, [O...

BVRI Light Curves for 22 Type Ia Supernovae (1998)

Riess, Adam G., Kirshner, Robert P., Schmidt, Brian P., Jha, Saurabh, Challis, Peter, Garnavich, Peter M., ...

We present 1210 Johnson/Cousins B,V,R, and I photometric observations of 22 recent type Ia supernovae (SNe Ia): SN 1993ac, SN 1993ae, SN 1994M, SN 1994S, SN 1994T, SN 1994Q, SN 1994ae, SN 1995D, SN...

New HST Observations of High Velocity Lyman Alpha and Balmer Alpha in SNR 1987A (1998)

Michael, Eli, McCray, Richard, Pun, C. S. J., Borkowski, Kazimierz, Garnavich, Peter, Challis, Peter, ...

We describe and model high velocity (~15,000 km/s) Lyman alpha and Balmer alpha emission from supernova remnant 1987A seen in September and October 1997 with the Space Telescope Imaging Spectrograph....

The High-Z Supernova Search: Measuring Cosmic Deceleration and Global Cur vature of the Universe Using Type Ia Supernovae (1998)

Schmidt, Brian P., Suntzeff, Nicholas B., Phillips, M. M., Schommer, Robert A., Clocchiatti, Alejandro, Kirshner, Robert P., ...

The High-Z Supernova Search is an international collaboration to discover and monitor type Ia supernovae (SN Ia) at $z > 0.2$ with the aim of measuring cosmic deceleration and global curvature. Our...

Observational Evidence from Supernovae for an Accelerating Universe and a Cosmological Constant (1998)

Riess, Adam G., Filippenko, Alexei V., Challis, Peter, Clocchiattia, Alejandro, Diercks, Alan, Garnavich, Peter M., ...

We present observations of 10 type Ia supernovae (SNe Ia) between 0.16 < z < 0.62. With previous data from our High-Z Supernova Search Team, this expanded set of 16 high-redshift supernovae and 34...

SN~1991T: Reflections of Past Glory (1994)

Schmidt, Brian P., Kirshner, Robert P., Leibundgut, Bruno, Wells, Lisa A., Porter, Alain C., Ruiz-Lapuente, Pilar, ...

We have obtained photometry and spectra of SN~1991T which extend more than 1000 days past maximum light, by far the longest a SN~Ia has been followed. Although SN~1991T exhibited nearly normal...