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Articles 1 - 7 of 7
Full-Text Articles in Physical Sciences and Mathematics
The 2d Distribution Of Iron-Rich Ejecta In The Remnant Of Sn 1885 In M31, Robert A. Fesen, Peter A. Höflich, Andrew J. S. Hamilton
The 2d Distribution Of Iron-Rich Ejecta In The Remnant Of Sn 1885 In M31, Robert A. Fesen, Peter A. Höflich, Andrew J. S. Hamilton
Dartmouth Scholarship
We present Hubble Space Telescope (HST) ultraviolet Fe i and Fe ii images of the remnant of Supernova 1885 (S And) which is observed in absorption against the bulge of the Andromeda galaxy, M31. We compare these Fe i and Fe ii absorption line images to previous HST absorption images of S And, of which the highest quality and theoretically cleanest is Ca ii H and K. Because the remnant is still in free expansion, these images provide a 2D look at the distribution of iron synthesized in this probable Type Ia explosion, thus providing insights and constraints …
The Broad-Lined Type Ic Sn 2012ap And The Nature Of Relativistic Supernovae Lacking A Gamma-Ray Burst Detection, D. Milisavljevic, R. Margutti, J. T. Parrent, A. M. Soderberg, R. A. Fesen
The Broad-Lined Type Ic Sn 2012ap And The Nature Of Relativistic Supernovae Lacking A Gamma-Ray Burst Detection, D. Milisavljevic, R. Margutti, J. T. Parrent, A. M. Soderberg, R. A. Fesen
Dartmouth Scholarship
We present ultraviolet, optical, and near-infrared observations of SN 2012ap, a broad-lined Type Ic supernova in the galaxy NGC 1729 that produced a relativistic and rapidly decelerating outflow without a gamma-ray burst signature. Photometry and spectroscopy follow the flux evolution from –13 to +272 days past the B-band maximum of –17.4 ± 0.5 mag. The spectra are dominated by Fe II, O I, and Ca II absorption lines at ejecta velocities of v ≈ 20,000 km s–1 that change slowly over time. Other spectral absorption lines are consistent with contributions from photospheric He I, and hydrogen may also …
Evidence For A Weak Wind From The Young Sun, Brian E. Wood, Hans-Reinhard Müller, Seth Redfield, Eric Edelman
Evidence For A Weak Wind From The Young Sun, Brian E. Wood, Hans-Reinhard Müller, Seth Redfield, Eric Edelman
Dartmouth Scholarship
The early history of the solar wind has remained largely a mystery due to the difficulty of detecting winds around young stars that can serve as analogs for the young Sun. Here we report on the detection of a wind from the 500 Myr old solar analog π1 UMa (G1.5 V), using spectroscopic observations from the Hubble Space Telescope. We detect H I Lyα absorption from the interaction region between the stellar wind and interstellar medium, i.e., the stellar astrosphere. With the assistance of hydrodynamic models of the π1 UMa astrosphere, we infer a wind only half as strong as …
Multi-Wavelength Observations Of Supernova 2011ei: Time-Dependent Classification Of Type Iib And Ib Supernovae And Implications For Their Progenitors, Dan Milisavljevic, Raffaella Margutti, Alicia M. Soderberg, Giuliano Pignata, Laura Chomiuk, Robert A. Fesen
Multi-Wavelength Observations Of Supernova 2011ei: Time-Dependent Classification Of Type Iib And Ib Supernovae And Implications For Their Progenitors, Dan Milisavljevic, Raffaella Margutti, Alicia M. Soderberg, Giuliano Pignata, Laura Chomiuk, Robert A. Fesen
Dartmouth Scholarship
We present X-ray, UV/optical, and radio observations of the stripped-envelope, core-collapse supernova (SN) 2011ei, one of the least luminous SNe IIb or Ib observed to date. Our observations begin with a discovery within 1 day of explosion and span several months afterward. Early optical spectra exhibit broad, Type II-like hydrogen Balmer profiles that subside rapidly and are replaced by Type Ib-like He-rich features on the timescale of one week. High-cadence monitoring of this transition suggests that absorption attributable to a high velocity (> 12,000 km/s) H-rich shell is not rare in Type Ib events. Radio observations imply a shock velocity …
Analysis Of The Early-Time Optical Spectra Of Sn 2011fe In M101, J. T. Parrent, D. A. Howell, B. Friesen, R. C. Thomas
Analysis Of The Early-Time Optical Spectra Of Sn 2011fe In M101, J. T. Parrent, D. A. Howell, B. Friesen, R. C. Thomas
Dartmouth Scholarship
The nearby Type Ia supernova SN 2011fe in M101 (cz=241 km s^-1) provides a unique opportunity to study the early evolution of a "normal" Type Ia supernova, its compositional structure, and its elusive progenitor system. We present 18 high signal-to-noise spectra of SN 2011fe during its first month beginning 1.2 days post-explosion and with an average cadence of 1.8 days. This gives a clear picture of how various line-forming species are distributed within the outer layers of the ejecta, including that of unburned material (C+O). We follow the evolution of C II absorption features until they diminish near maximum light, …
Time Evolution Of The Reverse Shock In Sn 1006, P. Frank Winkler, Andrew J. S. Hamilton, Knox S. Long, Robert A. Fesen
Time Evolution Of The Reverse Shock In Sn 1006, P. Frank Winkler, Andrew J. S. Hamilton, Knox S. Long, Robert A. Fesen
Dartmouth Scholarship
The Schweizer-Middleditch star, located behind the SN 1006 remnant and near its center in projection, provides the opportunity to study cold, expanding ejecta within the SN 1006 shell through UV absorption. Especially notable is an extremely sharp red edge to the Si II 1260 Å feature, which stems from the fastest moving ejecta on the far side of the SN 1006 shell—material that is just encountering the reverse shock. Comparing Hubble Space Telescope far-UV spectra obtained with the Cosmic Origins Spectrograph in 2010 and with the Space Telescope Imaging Spectrograph in 1999, we have measured the change in this feature …
A Study Of Carbon Features In Type Ia Supernova Spectra, Jerod T. Parrent, R. C. Thomas, Robert A. Fesen, G. H. Marion
A Study Of Carbon Features In Type Ia Supernova Spectra, Jerod T. Parrent, R. C. Thomas, Robert A. Fesen, G. H. Marion
Dartmouth Scholarship
One of the major differences between various explosion scenarios of Type Ia supernovae (SNe Ia) is the remaining amount of unburned (C+O) material and its velocity distribution within the expanding ejecta. While oxygen absorption features are not uncommon in the spectra of SNe Ia before maximum light, the presence of strong carbon absorption has been reported only in a minority of objects, typically during the pre-maximum phase. The reported low frequency of carbon detections may be due to low signal-to-noise data, low abundance of unburned material, line blending between C II 6580 and Si II 6355, ejecta temperature differences, asymmetrical …