Ib Supernovae Research Articles

Optical, Ultraviolet, and Infrared Observations of SN 1993J

SummaryWe review the existing set of optical/UV/IR observations of Supernova 1993J, concentrating heavily on optical data because these are by far the most plentiful. Some results from theoretical modeling of the observations are also discussed. SN 1993J has provided the best observational evidence for the transformation of a SN from one spectral type to another, thereby providing a link between Type II and Type Ib supernovae (SNe). This has strengthened the argument that SNe Ib (and, by extension, SNe Ic) are core-collapse events. SN 1993J has remained relatively bright for 10 years; its late-time emission comes from the collision of supernova ejecta with circumstellar gas that was released by the progenitor prior to the explosion. The circumstellar material shows strong evidence of CNO processing.

Photometric Identification of Young Stripped‐Core Supernovae

ABSTRACTWe present a method designed to identify the spectral type of young (less than ∼30 days after explosion) and nearby (z≲0.05) supernovae (SNe) using their broadband colors. In particular, we show that stripped‐core SNe (i.e., hydrogen‐deficient core‐collapse events, spectroscopically defined as SNe Ib and Ic, including broad‐lined SN 1998bw–like events) can be clearly distinguished from other types of SNe. Using the full census of nearby SNe discovered during the year 2002, we estimate the impact that prompt multiband photometry obtained by 1 m class telescopes would have on the early identification of stripped‐core events. Combining this new approach with ongoing spectroscopic follow‐up programs, one can expect ∼20 nearby, stripped‐core events to be identified each year around or before maximum light. Follow‐up studies, including prompt, multi‐epoch optical spectroscopy and spectropolarimetry, as well as radio and X‐ray observations, could greatly increase our understanding of these events and shed new light on their association with cosmological gamma‐ray bursts.

Searching Hubble Space Telescope Images for Core-Collapse Supernova Progenitors

Identifying the massive progenitor stars that give rise to core-collapse supernovae (SNe) is one of the main pursuits of supernova and stellar evolution studies, and is essential for understanding the birth of pulsars. Using ground-based images of recent, nearby SNe obtained primarily with the Katzman Automatic Imaging Telescope (KAIT), astrometry from 2MASS, and archival images from the Hubble Space Telescope (HST), we have attempted the direct identification of the progenitors of 16 Type II and Type Ib/c SNe. We may have identified the progenitors of the Type II SNe 1999br and 1999ev, the Type Ib SNe 2001B and 2001is, and the Type Ic SN 1999bu, possibly doubling the number of known SN progenitors. For the remaining SNe, limits placed on the absolute magnitude and color (when available) of the progenitor allows us to place limits on the progenitor's mass. Specifically, we have been able to place a relatively stringent limit on the progenitor of the Type II-P SN 2001du in NGC 1365, consistent with the limits placed on the masses of other Type II-P SNe. We have also recently identified the progenitor of the Type II-P SN 2003gd in Messier 74.

Supernova hosts for gamma-ray burst jets: dynamical constraints

I constrain a possible supernova origin for gamma-ray bursts (GRBs) by modelling the dynamical interaction between a relativistic jet and a stellar envelope surrounding it. The delay in observer time introduced by the jet traversing the envelope should not be long compared with the duration of gamma-ray emission; also, the jet should not be swallowed by the spherical explosion it powers. The only stellar progenitors that comfortably satisfy these constraints, if one assumes that jets move ballistically within their host stars, are compact carbon–oxygen or helium post-Wolf–Rayet stars (type Ic or Ib supernovae); type II supernovae are ruled out. Notably, very massive stars do not appear to be capable of producing the observed bursts at any redshift unless the stellar envelope is stripped prior to collapse. The presence of a dense stellar wind places an upper limit on the Lorentz factor of the jet in the internal shock model; however, this constraint may be evaded if the wind is swept forward by a photon precursor. Shock breakout and cocoon blowout are considered individually; neither presents a likely source of precursors for cosmological GRBs. These envelope constraints could conceivably be circumvented if jets are laterally pressure-confined while traversing the outer stellar envelope. If so, jets responsible for observed GRBs must have been launched from a region several hundred kilometres wide, have been crossed by strong shocks, or have mixed with envelope material as they travel. A phase of pressure confinement and mixing would imprint correlations among jets that may explain observed GRB variability–luminosity and lag–luminosity correlations.

Classifications of the Host Galaxies of Supernovae, Set II

ABSTRACTClassifications on the DDO system are given for an additional 231 host galaxies of supernovae that have been discovered during the course of the Lick Observatory Supernova Search with the Katzman Automatic Imaging Telescope (KAIT). This brings the total number of hosts of supernovae (SNe) discovered (or independently rediscovered) by KAIT, which have so far been classified on a homogeneous system, to 408. The probability that SNe Ia and SNe II have a different distribution of host‐galaxy Hubble types is found to be 99.7%. A significant difference is also found between the distributions of the host galaxies of SNe Ia and of SNe Ibc (defined here to include SNe Ib, Ib/c, and Ic). However, no significant difference is detected between the frequency distributions of the host galaxies of SNe II and SNe IIn. This suggests that SNe IIn are generally not SNe Ia embedded in circumstellar material that are masquerading as SNe II. Furthermore, no significant difference is found between the distribution of the Hubble types of the hosts of SNe Ibc and of SNe II. Additionally, SNe II‐P and SNe II‐L are found to occur among similar stellar populations. The ratio of the number of SNe Ia‐pec to normal SNe Ia appears to be higher in early‐type galaxies than it is in galaxies of later morphological types. This suggests that the ancestors of SNe Ia‐pec may differ systematically in age or composition from the progenitors of normal SNe Ia. Unexpectedly, five SNe of Types Ib/c, II, and IIn (all of which are thought to have massive progenitors) are found in host galaxies that are nominally classified as types E and S0. However, in each case the galaxy classification is uncertain, or newly inspected images show evidence suggesting a later classification. Among these five objects, NGC 3720, the host galaxy of SN 2002at, was apparently misidentified in the Carnegie Atlas of Galaxies.

A Search for Core‐Collapse Supernova Progenitors in Hubble Space Telescope Images11Based on observations made with the NASA/ESA Hubble Space Telescope, obtained from the data archive of the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy (AURA), Inc., under NASA contract NAS 5‐26555.

ABSTRACTIdentifying the massive progenitor stars that give rise to core‐collapse supernovae (SNe) is one of the main pursuits of supernova and stellar evolution studies. Using ground‐based images of recent, nearby SNe obtained primarily with the Katzman Automatic Imaging Telescope, astrometry from the Two Micron All Sky Survey, and archival images from the Hubble Space Telescope, we have attempted the direct identification of the progenitors of 16 Type II and Type Ib/c SNe. We may have identified the progenitors of the Type II SNe 1999br in NGC 4900, 1999ev in NGC 4274, and 2001du in NGC 1365 as supergiant stars with M0V ≈ -6 mag in all three cases. We may have also identified the progenitors of the Type Ib SNe 2001B in IC 391 and 2001is in NGC 1961 as very luminous supergiants with M0V ≈ -8 to −9 mag, and possibly the progenitor of the Type Ic SN 1999bu in NGC 3786 as a supergiant with M0V ≈ -7.5 mag. Additionally, we have recovered at late times SNe 1999dn in NGC 7714, 2000C in NGC 2415, and 2000ew in NGC 3810, although none of these had detectable progenitors on pre‐supernova images. In fact, for the remaining SNe only limits can be placed on the absolute magnitude and color (when available) of the progenitor. The detected Type II progenitors and limits are consistent with red supergiants as progenitor stars, although possibly not as red as we had expected. Our results for the Type Ib/c SNe do not strongly constrain either Wolf‐Rayet stars or massive interacting binary systems as progenitors.

The Spectral Characteristics of Stripped‐Envelope Supernovae

Supernovae (SNe) of Type Ib and Ic are distinguished by what they lack. They do not have the hydrogen lines indicative of Type II SNe, nor do they show the silicon absorption feature near 6150 A that is the hallmark of Type Ia SNe. (Type Ib SNe show helium absorption lines, while Type Ic SNe do not.) Type Ib and Ic SNe are rare and remain fairly mysterious objects. As they are thought to result from progenitors that have lost their massive envelopes, they are referred to as “stripped-envelope” SNe. We present various studies of optical spectra of SNe Ib/c and the metamorphosing SNe that link them to SNe II as core-collapse events. The spectroscopic characteristics of SNe Ib and Ic may help resolve questions about the nature of their progenitors. SN 1993J appeared originally to be a Type II SN, but it underwent a dramatic transformation to one resembling a Type Ib, although the hydrogen lines never completely faded away. This metamorphosis is seen in the 42 low-dispersion spectra shown by T. Matheson et al. (2000, AJ, 120, 1487). Detailed analysis of the SN 1993J spectra is presented by T. Matheson et al. (2000, AJ, 120, 1499). The spectra show that the ejecta are clumped, especially the synthesized oxygen. The calcium emission is smooth, implying that only preexisting calcium contributes to the emission. The late-time spectra exhibit signs of circumstellar interaction with a roughly spherical shell. Some emission lines develop a two-horned profile, indicating the formation of a flattened, disklike emission source. SN 1999cq exhibits the first unambiguous detection of helium emission lines in SNe Ic (T. Matheson et al. 2000, AJ, 119, 2303). They are of intermediate velocity width and appear to show the presence of dense circumstellar material composed of almost pure helium. This material may be stellar matter lost through a dense wind or mass transfer to a companion. We also present more than 80 spectra of various SNe Ib and Ic (T. Matheson et al. 2001, AJ, 121, 1648). SNe Ib are found to exhibit fairly homogeneous spectra and helium line strength. The relative depths of the helium absorption lines appear to provide a measurement of the temporal evolution of SNe Ib. SNe Ib and Ic are shown to have distinguishing characteristics other than the presence or absence of helium lines. SNe Ic have clearly broader nebular-phase emission lines, indicating that SNe Ic have a higher explosion energy and/or lower envelope mass than SNe Ib. SNe Ic also have stronger permitted oxygen lines at early times, implying that they are less diluted by a massive helium envelope. This lends strength to the argument that the difference between SNe Ib and SNe Ic arises from the constituents of the overlying envelope of the star at the time of core collapse, rather than the extent of mixing of radioactive nickel into the helium layers of the progenitor. SNe Ic themselves are heterogeneous, with diverse spectroscopic characteristics. No strong evidence for helium is found in SNe Ic, although some objects may have a low level of helium. These may be SNe that bridge the gap between SNe Ib and Ic.

The Metamorphosis of SN 1998bw

We present and discuss the photometric and spectroscopic evolution of the peculiar SN 1998bw, associated with GRB 980425, through an analysis of optical and near-IR data collected at ESOLa Silla. The spectroscopic data, spanning the period from day ( 9t o day)376 (relative to B maximum), have shown that this supernova (SN) was unprecedented, although somewhat similar to SN 1997ef. Maximum expansion velocities as high as 3 ) 104 km s~1 to some extent mask its resemblance to other Type Ic SNe. At intermediate phases, between photospheric and fully nebular, the expansion velocities (D104 km s~1) remained exceptionally high compared to those of other recorded core-collapse SNe at a similar phase. The mild linear polarization detected at early epochs suggests the presence of asymmetry in the emitting material. The degree of asymmetry, however, cannot be decoded from these measurements alone. The He I 1.083 and 2.058 km lines are identi—ed, and He is suggested to lie in an outer region of the envelope. The temporal behavior of the —uxes and pro—les of emission lines of Mg I) j4571, (O I) jj6300, 6364, and a feature ascribed to Fe are traced to stimulate future modeling work. The uniqueness of SN 1998bw became less obvious once it entered the fully nebular phase (after 1 yr), when it was very similar to other Type Ib/cIIb objects, such as the Type Ib SN 1996N and the Type IIb SN 1993J, even though SN 1998bw was 1.4 mag brighter than SN 1993J and 3 mag brighter than SN 1996N at a com- parable phase. The late-phase optical photometry, which extends up to 403 days after B maximum, shows that the SN luminosity declined exponentially but substantially faster than the decay rate of 56Co. The ultraviolet-optical-infrared bolometric light curve, constructed using all available optical data and the early JHK photometry presented in this work, shows a slight —attening starting on about day )300. Since no clear evidence of ejecta-wind interaction was found in the late-time spectroscopy (see also the work of Sollerman and coworkers), this may be due to the contribution of the positrons since most c-rays escape thermalization at this phase. A contribution from the superposed H II region cannot, however, be excluded. Subject headings: gamma rays: burstssupernovae: generalsupernovae: individual (SN 1998bw)

The Type Ic SN 1990B in NGC 4568

We present a study of the Type Ic supernova (SN) 1990B that includes most of the observations obtained from around the world. The combined data set comprises 84 BV(RI)c photometric points spanning approximately 360 days after maximum light and 14 spectra from 5 up to ~150 days after maximum light. In contrast to other Type Ic SNe, SN 1990B did not display a weak but distinct He I λ5876 line indicating that its He content was smaller or that the He layers were rather effectively shielded from the radioactive matter in the ejecta. The behavior of the Na I D line, however, suggests that He I λ5876 was blended with it. SN 1990B appeared on a sharply varying background that complicates the usual techniques of digital photometry. In order to do unbiased photometry, we modeled and subtracted the background of each image with the SN using images of NGC 4568 taken ~2500 days after the explosion, when SN 1990B had faded beyond detection. We compare the performance of standard point-spread function fitting photometry of the SN in the images with and without the background of the parent galaxy and find the results to differ systematically at late times. The photometry done on the images with the background light of NGC 4568 subtracted shows the light curves of SN 1990B to be of the slow Type Ic variety, with a slope steeper than that of the Type Ib SN 1983N or the Type II transition (Type IIb) SN 1993J but slower than that of the Type Ic SN 1994I. We estimate the reddening by foreground matter in the Galaxy and NGC 4568 and compute BV(RI)c light curves spanning ~110 days after maximum light.

Gamma‐Ray Line Signals from Supernovae within 100 Mpc

The average number of supernovae per year detectable by γ-rays emitted during the decay of 56Ni to 56Fe is estimated for galaxies within 100 Mpc as a function of limiting sensitivity using standard supernova yields and the Sternberg and Asiago supernova catalogs. An instrument having a broad-line (5000 km s-1) sensitivity of 2 × 10-6 γ s-1 cm-2 should detect a minimum of 1.0 ± 0.5 Type Ia supernovae per year, and observe all Type Ia events from the Virgo, Fornax, and possibly the Hydra galaxy clusters. Roughly 10%-30% of all Type Ia supernovae within 100 Mpc are detectable at this flux sensitivity. Instruments having broad-line flux sensitivities larger than 1.5 × 10-5 γ s-1 cm-2 will probably only detect rare Type Ia supernovae within 10 Mpc, such as SN 1972E or SN 1991T. Flux sensitivities of 2 × 10-6 γ s-1 cm-2 to intermediate-width γ-ray lines should enable the detection of a minimum of 0.2 ± 0.2 Type Ib and Type Ic supernovae per year, and easily allow events similar to SN 1983N and SN 1985F to be seen. Instruments of the near future will not detect the narrow-line γ rays from any Type II supernovae that originate beyond the Local Group of galaxies. These number and rate estimates provide guidelines for the design of future γ-ray missions.

OPTICAL SPECTRA OF SUPERNOVAE

▪ Abstract The temporal evolution of the optical spectra of various types of supernovae (SNe) is illustrated, in part to aid observers classifying supernova candidates. Type II SNe are defined by the presence of hydrogen, and they exhibit a very wide variety of photometric and spectroscopic properties. Among hydrogen-deficient SNe (Type I), three subclasses are now known: those whose early-time spectra show strong Si II (Ia), prominent He I (Ib), or neither Si II nor He I (Ic). The late-time spectra of SNe Ia consist of a multitude of blended emission lines of iron-group elements; in sharp contrast, those of SNe Ib and SNe Ic (which are similar to each other) are dominated by several relatively unblended lines of intermediate-mass elements. Although SNe Ia, which result from the thermonuclear runaway of white dwarfs, constitute a rather homogeneous subclass, important variations in their photometric and spectroscopic properties are undeniably present. SNe Ib/Ic probably result from core collapse in massive stars largely stripped of their hydrogen (Ib) and helium (Ic) envelopes, and hence they are physically related to SNe II. Indeed, the progenitors of some SNe II seem to have only a low-mass skin of hydrogen; their spectra gradually evolve to resemble those of SNe Ib. In addition to the two well-known photometric subclasses (linear and plateau) of SNe II, which may exhibit minor spectroscopic differences, there is a new subclass (SNe IIn) distinguished by relatively narrow emission lines with little or no P Cygni absorption component and slowly declining light curves. These objects probably have unusually dense circumstellar gas with which the ejecta interact.

Peak Brightnesses of Historical Supernovae and the Hubble Constant

view Abstract Citations (64) References (139) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Peak Brightnesses of Historical Supernovae and the Hubble Constant Schaefer, Bradley E. Abstract This paper reports on the peak magnitudes (mmax) and peak absolute magnitudes (Mmax) of SN 1604, SN 1572, SN 1006, and SN 185 utilizing three techniques that have not been previously applied to the historical supernovae. SN 1604 is at a distance (D) of 3.4 + 0.3 kpc, with a visual extinction (A) of 3.27 + 0.14 and is unlikely to be a Type Ia supernova. Its light curve shape is like that of a fast Type Ia event with mmax = -3.02+0.10 and Mmax = -18.95+0.26. SN 1572 is at D=2.35+0.20 kpc, with A = 225 + 0 16 and is likely to be a Type Ia or Ib supernova. Its light curve shape is like that of a very fast Type Ia event with mmax = -4.53 + 0.18 and Mmax = -18.64 + 0.31. SN 1006 is most likely a Type Ia event at 1.59 + 0.13 kpc with an extinction of 0.32 + 0.03 and a peak near - 5 mag. Even though the available light curve is sparse and crude, the supernova is certainly subluminous with a peak absolute magnitude of approximately -17. SN 185 has a peak magnitude that can only be constrained to be brighter than roughly -7.5, has an uncertain remnant, and is unlikely to even be a supernova. These four historical supernovae are useless for solving the Hubble constant question for three reasons: First, none of them is guaranteed to be a Type Ia event and SN 185 is unlikely to even be a supernova. Second, the various calibration, template, and procedural problems combine to make the uncertainties large. Third, the measurement errors alone yield uncertainties that are sufficiently large to preclude a solution of the Hubble constant problem. Publication: The Astrophysical Journal Pub Date: March 1996 DOI: 10.1086/176906 Bibcode: 1996ApJ...459..438S Keywords: COSMOLOGY: OBSERVATIONS; COSMOLOGY: DISTANCE SCALE; STARS: SUPERNOVAE: INDIVIDUAL ALPHANUMERIC: SN 185; STARS: SUPERNOVAE: INDIVIDUAL ALPHANUMERIC: SN 1006; STARS: SUPERNOVAE: INDIVIDUAL ALPHANUMERIC: SN 1572A; STARS: SUPERNOVAE: INDIVIDUAL ALPHANUMERIC: SN 1604 full text sources ADS | data products SIMBAD (18)

DISTRIBUTION OF SUPERNOVAE RELATIVE TO SPIRAL ARMS AND H II REGIONS

ABSTRACT We have studied the association of supernovae in spiral galaxies with sites of recent star formation--spiral arms and H II regions. It is shown that supernovae (SNe) of Types Ia, Ib and II exhibit concentration to spiral arms and their distributions over the distance to the nearest spiral arm to not differ significantly. This result is confirmed by a Kolmogorov-Smirnov test comparison with the distance distributions, expected if SNe are distributed randomly inside the model galaxy. SNe of Types Ib and II show a strong concentration towards H II regions, while distribution of SNe Ia can be explained by chance superposition. All studied distributions of SNe Ib and II show striking similarity, which suggests that their progenitors are massive stars with similar ages and initial masses. The association of SNe Ia with spiral arms suggests that their progenitors in spiral galaxies are likely to be intermediate mass stars.

The alpha-process and the r-process

The paper explores the alpha-rich freeze-out for values of neutron excesses larger than previously treated, and reports the discovery of nuclear systematics that, for neutron excesses greater than about 0.05, allow the creation of heavier elements all the way up to A of about 100, even when most of the ejecta is in the form of heavy elements. It is found that a large part of the nuclear flow in the r-process may be carried by charged particle reactions up to about A of about 100. It is speculated that the site of these processes is the high-entropy 'wind' of a young neutron star in which neutrino energy deposition is driving mass loss. The pass of r-process ejected per supernova is expected to be about 0.0001 solar mass per Type II or Ib supernova, but this is sensitive to details of the presupernova structure, the explosion mechanism, and the amount of material that falls back onto the neutron star when the reverse shock arrives there.

Radio emission from supernovae. I - One to twelve year old supernovae

As part of a continuing study of the radio emission from supernovae (SNs), we have used the VLA at 6 cm in 1982 May to observe all recorded optical supernovae brighter than 14.0 mag from SN 1970A to SN 1981A, i.e., all SNs with ages between 1 and 12 yr at the time of observation. Apart from the known radio supernovae (RSNs) in this age group (SN 1970G, SN 1979C, and SN 1980K), we obtained no new detections of radio emission from any of the objects to a limit of ~0.5 mJy. Consideration of these new results and other radio observations of SNs reported in the literature, combined with theoretical models, allows us to establish (limits on) mass-loss rates from the presupernova systems. The conclusions are that (1) Type Ia SNs originate in systems which contain very little circumstellar material at the time of explosion and which are very different from the systems which originate Type Ib SNs and (2) Type Il SNs, with a few obvious exceptions, originate in systems with the high presupernova mass-loss rates expected from red supergiant progenitors with original main-sequence masses greater than ~8 M_sun_. Most Type II SNs brighter than 12 mag should be detectable with the VLA if observed early enough.

Taxonomy of Supernovae

AbstractI review the observed properties of supernovae (SNe), concentrating on recent results obtained from high-quality optical spectra. Although most SNe Ia have similar characteristics at comparable phases, there are some notable variations, particularly in the velocities of the ejecta. Moreover, there is very preliminary evidence for significant differences between the spectra of SNe Ia in H II regions and in elliptical galaxies. SNe II exhibit a wide range of spectral properties, as expected if they are produced by massive stars. At late times strong lines of [O I] and [Ca II] appear in most SNe II, including SN 1987A. In some objects, however, these are absent; the spectrum of SN 1987F, for instance, closely resembled that of a Seyfert 1 nucleus, with prominent H I and Fe II emission lines. Type Ib SNe, which lack the 6150Â absorption band typical of SNe la near maximum brightness, develop strong emission lines of [O I] and [Ca II] many months past maximum, but hydrogen is absent. Hα emission with a P-Cygni profile has, on the other hand, been detected in the early-time spectrum of SN 1987K, an object which later became spectroscopically indistinguishable from an old SN Ib. There is evidence for very weak Hα in the early spectra of several additional SNe Ib. Moreover, 7 – 8 months past maximum the [O I]/Hα and [Ca II]/Hα intensity ratios in SN 1987A were higher than in a few other well-observed SNe II at corresponding times. Hence, Type II and Type Ib SNe may form a continuous sequence in which the mass of the hydrogen envelope is the main variable.