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Srinivasaragavan, G. P., Swain, V., O'Connor, B., Anand, S., Ahumada, T., Perley, D., . . . Wold, A. (2024). Characterizing the Ordinary Broad-line Type Ic SN 2023pel from the Energetic GRB 230812B. Astrophysical Journal Letters, 960(2), Article ID L18.
Open this publication in new window or tab >>Characterizing the Ordinary Broad-line Type Ic SN 2023pel from the Energetic GRB 230812B
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2024 (English)In: Astrophysical Journal Letters, ISSN 2041-8205, E-ISSN 2041-8213, Vol. 960, no 2, article id L18Article in journal (Refereed) Published
Abstract [en]

We report observations of the optical counterpart of the long gamma-ray burst (GRB) GRB 230812B and its associated supernova (SN) SN 2023pel. The proximity (z = 0.36) and high energy (Eγ,iso ∼ 1053 erg) make it an important event to study as a probe of the connection between massive star core collapse and relativistic jet formation. With a phenomenological power-law model for the optical afterglow, we find a late-time flattening consistent with the presence of an associated SN. SN 2023pel has an absolute peak r-band magnitude of Mr = −19.46 ± 0.18 mag (about as bright as SN 1998bw) and evolves on quicker timescales. Using a radioactive heating model, we derive a nickel mass powering the SN of MNi = 0.38 ± 0.01 M and a peak bolometric luminosity of Lbol ∼ 1.3 × 1043 erg s−1. We confirm SN 2023pel's classification as a broad-line Type Ic SN with a spectrum taken 15.5 days after its peak in the r band and derive a photospheric expansion velocity of vph = 11,300 ± 1600 km s−1 at that phase. Extrapolating this velocity to the time of maximum light, we derive the ejecta mass Mej = 1.0 ± 0.6 M and kinetic energy EKE = 1.3 +3.3/-1.2 x 1051 erg. We find that GRB 230812B/SN 2023pel has SN properties that are mostly consistent with the overall GRB-SN population. The lack of correlations found in the GRB-SN population between SN brightness and Eγ,iso for their associated GRBs across a broad range of 7 orders of magnitude provides further evidence that the central engine powering the relativistic ejecta is not coupled to the SN powering mechanism in GRB-SN systems.

National Category
Astronomy, Astrophysics and Cosmology
Identifiers
urn:nbn:se:su:diva-226049 (URN)10.3847/2041-8213/ad16e7 (DOI)001138589900001 ()2-s2.0-85182349337 (Scopus ID)
Available from: 2024-02-12 Created: 2024-02-12 Last updated: 2024-02-12Bibliographically approved
Strotjohann, N. L., Ofek, E. O., Gal-Yam, A., Sollerman, J., Chen, P., Yaron, O., . . . Purdum, J. (2024). Search for Supernova Progenitor Stars with ZTF and LSST. Astrophysical Journal, 960(1), Article ID 72.
Open this publication in new window or tab >>Search for Supernova Progenitor Stars with ZTF and LSST
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2024 (English)In: Astrophysical Journal, ISSN 0004-637X, E-ISSN 1538-4357, Vol. 960, no 1, article id 72Article in journal (Refereed) Published
Abstract [en]

The direct detection of core-collapse supernova (SN) progenitor stars is a powerful way of probing the last stages of stellar evolution. However, detections in archival Hubble Space Telescope images are limited to about one detection per year. Here, we explore whether we can increase the detection rate by using data from ground-based wide-field surveys. Due to crowding and atmospheric blurring, progenitor stars can typically not be identified in preexplosion images alone. Instead, we combine many pre-SN and late-time images to search for the disappearance of the progenitor star. As a proof of concept, we implement our search of ZTF data. For a few hundred images, we achieve limiting magnitudes of ∼23 mag in the g and r bands. However, no progenitor stars or long-lived outbursts are detected for 29 SNe within z ≤ 0.01, and the ZTF limits are typically several magnitudes less constraining than detected progenitors in the literature. Next, we estimate progenitor detection rates for the Legacy Survey of Space and Time (LSST) with the Vera C. Rubin telescope by simulating a population of nearby SNe. The background from bright host galaxies reduces the nominal LSST sensitivity by, on average, 0.4 mag. Over the 10 yr survey, we expect the detection of ∼50 red supergiant progenitors and several yellow and blue supergiants. The progenitors of Type Ib and Ic SNe will be detectable if they are brighter than −4.7 or −4.0 mag in the LSST i band, respectively. In addition, we expect the detection of hundreds of pre-SN outbursts depending on their brightness and duration.

Keywords
Core-collapse supernovae, Massive stars, Red supergiant stars, Sky surveys
National Category
Astronomy, Astrophysics and Cosmology
Identifiers
urn:nbn:se:su:diva-225381 (URN)10.3847/1538-4357/ad06b6 (DOI)001132042000001 ()2-s2.0-85181149974 (Scopus ID)
Available from: 2024-01-19 Created: 2024-01-19 Last updated: 2024-01-19Bibliographically approved
Coughlin, M. W., Sollerman, J. & Sharma, V. (2023). A Data Science Platform to Enable Time-domain Astronomy. Astrophysical Journal Supplement Series, 267(2), Article ID 31.
Open this publication in new window or tab >>A Data Science Platform to Enable Time-domain Astronomy
2023 (English)In: Astrophysical Journal Supplement Series, ISSN 0067-0049, E-ISSN 1538-4365, Vol. 267, no 2, article id 31Article in journal (Refereed) Published
Abstract [en]

SkyPortal is an open-source software package designed to discover interesting transients efficiently, manage follow-up, perform characterization, and visualize the results. By enabling fast access to archival and catalog data, crossmatching heterogeneous data streams, and the triggering and monitoring of on-demand observations for further characterization, a SkyPortal-based platform has been operating at scale for >2 yr for the Zwicky Transient Facility Phase II community, with hundreds of users, containing tens of millions of time-domain sources, interacting with dozens of telescopes, and enabling community reporting. While SkyPortal emphasizes rich user experiences across common front-end workflows, recognizing that scientific inquiry is increasingly performed programmatically, SkyPortal also surfaces an extensive and well-documented application programming interface system. From back-end and front-end software to data science analysis tools and visualization frameworks, the SkyPortal design emphasizes the reuse and leveraging of best-in-class approaches, with a strong extensibility ethos. For instance, SkyPortal now leverages ChatGPT large language models to generate and surface source-level human-readable summaries automatically. With the imminent restart of the next generation of gravitational-wave detectors, SkyPortal now also includes dedicated multimessenger features addressing the requirements of rapid multimessenger follow-up: multitelescope management, team/group organizing interfaces, and crossmatching of multimessenger data streams with time-domain optical surveys, with interfaces sufficiently intuitive for newcomers to the field. This paper focuses on the detailed implementations, capabilities, and early science results that establish SkyPortal as a community software package ready to take on the data science challenges and opportunities presented by this next chapter in the multimessenger era.

Keywords
Open source software, Astronomy software, Time domain astronomy
National Category
Astronomy, Astrophysics and Cosmology Computer Sciences
Identifiers
urn:nbn:se:su:diva-223401 (URN)10.3847/1538-4365/acdee1 (DOI)001041591800001 ()2-s2.0-85169024658 (Scopus ID)
Available from: 2023-11-02 Created: 2023-11-02 Last updated: 2023-11-02Bibliographically approved
Levan, A. J., Malesani, D. B., Gompertz, B. P., Nugent, A. E., Nicholl, M., Oates, S. R., . . . Tanvir, N. R. (2023). A long-duration gamma-ray burst of dynamical origin from the nucleus of an ancient galaxy. Nature Astronomy, 7(8), 976-985
Open this publication in new window or tab >>A long-duration gamma-ray burst of dynamical origin from the nucleus of an ancient galaxy
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2023 (English)In: Nature Astronomy, E-ISSN 2397-3366, Vol. 7, no 8, p. 976-985Article in journal (Refereed) Published
Abstract [en]

The majority of long-duration (>2 s) gamma-ray bursts (GRBs) arise from the collapse of massive stars, with a small proportion created from the merger of compact objects. Most of these systems form via standard stellar evolution pathways. However, a fraction of GRBs may result from dynamical interactions in dense environments. These channels could also contribute substantially to the samples of compact object mergers detected as gravitational wave sources. Here we report the case of GRB 191019A, a long GRB (a duration of T90 = 64.4 ± 4.5 s), which we pinpoint close (⪅100 pc projected) to the nucleus of an ancient (>1 Gyr old) host galaxy at z = 0.248. The lack of evidence for star formation and deep limits on any supernova emission disfavour a massive star origin. The most likely route for progenitor formation is via dynamical interactions in the dense nucleus of the host. The progenitor, in this case, could be a compact object merger. These may form in dense nuclear clusters or originate in a gaseous disc around the supermassive black hole. Identifying, to the best of our knowledge, a first example of a dynamically produced GRB demonstrates the role that such bursts may have in probing dense environments and constraining dynamical fractions in gravitational wave populations.

National Category
Astronomy, Astrophysics and Cosmology
Identifiers
urn:nbn:se:su:diva-221078 (URN)10.1038/s41550-023-01998-8 (DOI)001019740000004 ()2-s2.0-85162673864 (Scopus ID)
Available from: 2023-09-25 Created: 2023-09-25 Last updated: 2023-09-25Bibliographically approved
Karamehmetoglu, E., Sollerman, J., Taddia, F., Barbarino, C., Feindt, U., Fremling, C., . . . Zapartas, E. (2023). A population of Type Ibc supernovae with massive progenitors Broad lightcurves not uncommon in (i)PTF. Astronomy and Astrophysics, 678, Article ID A87.
Open this publication in new window or tab >>A population of Type Ibc supernovae with massive progenitors Broad lightcurves not uncommon in (i)PTF
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2023 (English)In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 678, article id A87Article in journal (Refereed) Published
Abstract [en]

If high-mass stars (≳20 − 25 M) are the progenitors of stripped-envelope (SE) supernovae (SNe), their massive ejecta should lead to broad, long-duration lightcurves. Instead, literature samples of SE SNe have reported relatively narrow lightcurves corresponding to ejecta masses between 1 − 4 M that favor intermediate-mass progenitors (≲20 − 25 M). Working with an untargeted sample from a single telescope to better constrain their rates, we searched the Palomar Transient Factory (PTF) and intermediate-PTF (iPTF) sample of SNe for SE SNe with broad lightcurves. Using a simple observational marker of g- or r-band lightcurve stretch compared to a template to measure broadness, we identified eight significantly broader Type Ibc SNe after applying quantitative sample selection criteria. The lightcurves, broad-band colors, and spectra of these SNe are found to evolve more slowly relative to typical Type Ibc SNe, proportional with the stretch parameter. Bolometric lightcurve modeling and their nebular spectra indicate high ejecta masses and nickel masses, assuming radioactive decay powering. Additionally, these objects are preferentially located in low-metallicity host galaxies with high star formation rates, which may account for their massive progenitors, as well as their relative absence from the literature. Our study thus supports the link between broad lightcurves (as measured by stretch) and high-mass progenitor stars in SE SNe with independent evidence from bolometric lightcurve modeling, nebular spectra, host environment properties, and photometric evolution. In the first systematic search of its kind using an untargeted sample, we used the stretch distribution to identify a higher than previously appreciated fraction of SE SNe with broad lightcurves (∼13%). Correcting for Malmquist and lightcurve duration observational biases, we conservatively estimate that a minimum of ∼6% of SE SNe are consistent with high-mass progenitors. This result has implications for the progenitor channels of SE SNe, including late stages of massive stellar evolution, the origin of the observed oxygen fraction in the universe, and formation channels for stellar-mass black holes.

Keywords
supernovae: general, methods: statistical, surveys, methods: data analysis, techniques: photometric
National Category
Astronomy, Astrophysics and Cosmology
Identifiers
urn:nbn:se:su:diva-223850 (URN)10.1051/0004-6361/202245231 (DOI)001084587200004 ()2-s2.0-85175010454 (Scopus ID)
Available from: 2023-11-20 Created: 2023-11-20 Last updated: 2023-11-20Bibliographically approved
Kool, E. C., Pearson Johansson, J., Sollerman, J., Moldón, J., Moriya, T. J., Mattila, S., . . . Stern, D. (2023). A radio-detected type Ia supernova with helium-rich circumstellar material. Nature, 617(7961), 477-482
Open this publication in new window or tab >>A radio-detected type Ia supernova with helium-rich circumstellar material
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2023 (English)In: Nature, ISSN 0028-0836, E-ISSN 1476-4687, Vol. 617, no 7961, p. 477-482Article in journal (Refereed) Published
Abstract [en]

Type Ia supernovae (SNe Ia) are thermonuclear explosions of degenerate white dwarf stars destabilized by mass accretion from a companion star1, but the nature of their progenitors remains poorly understood. A way to discriminate between progenitor systems is through radio observations; a non-degenerate companion star is expected to lose material through winds2 or binary interaction3 before explosion, and the supernova ejecta crashing into this nearby circumstellar material should result in radio synchrotron emission. However, despite extensive efforts, no type Ia supernova (SN Ia) has ever been detected at radio wavelengths, which suggests a clean environment and a companion star that is itself a degenerate white dwarf star4,5. Here we report on the study of SN 2020eyj, a SN Ia showing helium-rich circumstellar material, as demonstrated by its spectral features, infrared emission and, for the first time in a SN Ia to our knowledge, a radio counterpart. On the basis of our modelling, we conclude that the circumstellar material probably originates from a single-degenerate binary system in which a white dwarf accretes material from a helium donor star, an often proposed formation channel for SNe Ia (refs. 6,7). We describe how comprehensive radio follow-up of SN 2020eyj-like SNe Ia can improve the constraints on their progenitor systems.

National Category
Astronomy, Astrophysics and Cosmology
Identifiers
urn:nbn:se:su:diva-223960 (URN)10.1038/s41586-023-05916-w (DOI)001078324200011 ()37198310 (PubMedID)2-s2.0-85159611552 (Scopus ID)
Available from: 2023-11-24 Created: 2023-11-24 Last updated: 2023-11-24Bibliographically approved
Ho, A. Y. Q., Perley, D. A., Gal-Yam, A., Lunnan, R., Sollerman, J., Schulze, S., . . . Winters, J. M. (2023). A Search for Extragalactic Fast Blue Optical Transients in ZTF and the Rate of AT2018cow-like Transients. Astrophysical Journal, 949(2), Article ID 120.
Open this publication in new window or tab >>A Search for Extragalactic Fast Blue Optical Transients in ZTF and the Rate of AT2018cow-like Transients
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2023 (English)In: Astrophysical Journal, ISSN 0004-637X, E-ISSN 1538-4357, Vol. 949, no 2, article id 120Article in journal (Refereed) Published
Abstract [en]

We present a search for extragalactic fast blue optical transients (FBOTs) during Phase I of the Zwicky Transient Facility (ZTF). We identify 38 candidates with durations above half-maximum light 1 day < t (1/2) < 12 days, of which 28 have blue (g - r less than or similar to -0.2 mag) colors at peak light. Of the 38 transients (28 FBOTs), 19 (13) can be spectroscopically classified as core-collapse supernovae (SNe): 11 (8) H- or He-rich (Type II/IIb/Ib) SNe, 6 (4) interacting (Type IIn/Ibn) SNe, and 2 (1) H&He-poor (Type Ic/Ic-BL) SNe. Two FBOTs (published previously) had predominantly featureless spectra and luminous radio emission: AT2018lug (The Koala) and AT2020xnd (The Camel). Seven (five) did not have a definitive classification: AT 2020bdh showed tentative broad H alpha in emission, and AT 2020bot showed unidentified broad features and was 10 kpc offset from the center of an early-type galaxy. Ten (eight) have no spectroscopic observations or redshift measurements. We present multiwavelength (radio, millimeter, and/or X-ray) observations for five FBOTs (three Type Ibn, one Type IIn/Ibn, one Type IIb). Additionally, we search radio-survey (VLA and ASKAP) data to set limits on the presence of radio emission for 24 of the transients. All X-ray and radio observations resulted in nondetections; we rule out AT2018cow-like X-ray and radio behavior for five FBOTs and more luminous emission (such as that seen in the Camel) for four additional FBOTs. We conclude that exotic transients similar to AT2018cow, the Koala, and the Camel represent a rare subset of FBOTs and use ZTF's SN classification experiments to measure the rate to be at most 0.1% of the local core-collapse SN rate.

National Category
Astronomy, Astrophysics and Cosmology
Identifiers
urn:nbn:se:su:diva-218369 (URN)10.3847/1538-4357/acc533 (DOI)001001445700001 ()2-s2.0-85161632715 (Scopus ID)
Available from: 2023-06-27 Created: 2023-06-27 Last updated: 2023-06-27Bibliographically approved
Corsi, A., Ho, A. Y. Q., Cenko, S. B., Kulkarni, S. R., Anand, S., Yang, S., . . . Regnault, N. (2023). A Search for Relativistic Ejecta in a Sample of ZTF Broad-lined Type Ic Supernovae. Astrophysical Journal, 953(2), Article ID 179.
Open this publication in new window or tab >>A Search for Relativistic Ejecta in a Sample of ZTF Broad-lined Type Ic Supernovae
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2023 (English)In: Astrophysical Journal, ISSN 0004-637X, E-ISSN 1538-4357, Vol. 953, no 2, article id 179Article in journal (Refereed) Published
Abstract [en]

The dividing line between gamma-ray bursts (GRBs) and ordinary stripped-envelope core-collapse supernovae (SNe) is yet to be fully understood. Observationally mapping the variety of ejecta outcomes (ultrarelativistic, mildly relativistic, or nonrelativistic) in SNe of Type Ic with broad lines (Ic-BL) can provide a key test to stellar explosion models. However, this requires large samples of the rare SN Ic-BL events with follow-up observations in the radio, where fast ejecta can be probed largely free of geometry and viewing angle effects. Here, we present the results of a radio (and X-ray) follow-up campaign of 16 SNe Ic-BL detected by the Zwicky Transient Facility (ZTF). Our radio campaign resulted in four counterpart detections and 12 deep upper limits. None of the events in our sample is as relativistic as SN 1998bw and we constrain the fraction of SN 1998bw-like explosions to <19% (3σ Gaussian equivalent), a factor of ≈2 smaller than previously established. We exclude relativistic ejecta with radio luminosity densities in between ≈5 × 1027 erg s−1 Hz−1 and ≈1029 erg s−1 Hz−1 at t ≳ 20 days since explosion for ≈60% of the events in our sample. This shows that SNe Ic-BL similar to the GRB-associated SNe 1998bw, 2003lw, and 2010bh, or to the relativistic SNe 2009bb and iPTF17cw, are rare. Our results also exclude an association of the SNe Ic-BL in our sample with largely off-axis GRBs with energies E ≳ 1050 erg. The parameter space of SN 2006aj-like events (faint and fast-peaking radio emission) is, on the other hand, left largely unconstrained, and systematically exploring it represents a promising line of future research.

National Category
Astronomy, Astrophysics and Cosmology
Identifiers
urn:nbn:se:su:diva-221098 (URN)10.3847/1538-4357/acd3f2 (DOI)001051537800001 ()2-s2.0-85168605388 (Scopus ID)
Available from: 2023-09-18 Created: 2023-09-18 Last updated: 2023-09-18Bibliographically approved
Sharma, Y., Sollerman, J., Fremling, C., Kulkarni, S. R., De Kishalay, K., Irani, I., . . . Yao, Y. (2023). A Systematic Study of Ia-CSM Supernovae from the ZTF Bright Transient Survey. Astrophysical Journal, 948(1), Article ID 52.
Open this publication in new window or tab >>A Systematic Study of Ia-CSM Supernovae from the ZTF Bright Transient Survey
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2023 (English)In: Astrophysical Journal, ISSN 0004-637X, E-ISSN 1538-4357, Vol. 948, no 1, article id 52Article in journal (Refereed) Published
Abstract [en]

Among the supernovae (SNe) that show strong interaction with a circumstellar medium (CSM), there is a rare subclass of Type Ia supernovae, SNe Ia-CSM, which show strong narrow hydrogen emission lines much like SNe IIn but on top of a diluted Type Ia spectrum. The only previous systematic study of this class identified 16 SNe Ia-CSM, eight historic and eight from the Palomar Transient Factory (PTF). Now using the successor survey to PTF, the Zwicky Transient Facility (ZTF), we have classified 12 additional SNe Ia-CSM through the systematic Bright Transient Survey (BTS). Consistent with previous studies, we find these SNe to have slowly evolving optical light curves with peak absolute magnitudes between -19.1 and -21, spectra having weak H ss and large Balmer ldecrements of similar to 7. Out of the 10 SNe from our sample observed by NEOWISE, nine have 3 sigma detections, with some SNe showing a reduction in the red wing of Ha, indicative of newly formed dust. We do not find our SN Ia-CSM sample to have a significantly different distribution of equivalent widths of He I.5876 than SNe IIn as observed in Silverman et al. The hosts tend to be late-type galaxies with recent star formation. We derive a rate estimate of 29+(27)(21) Gpc(-3) yr(-1) for SNe Ia-CSM, which is similar to 0.02%-0.2% of the SN Ia rate. We also identify six ambiguous SNe IIn/Ia-CSM in the BTS sample and including them gives an upper limit rate of 0.07%-0.8%. This work nearly doubles the sample of well-studied Ia-CSM objects in Silverman et al., increasing the total number to 28.

Keywords
Unified Astronomy Thesaurus concepts: Supernovae (1668), Type Ia supernovae (1728)
National Category
Astronomy, Astrophysics and Cosmology
Identifiers
urn:nbn:se:su:diva-218365 (URN)10.3847/1538-4357/acbc16 (DOI)000982386400001 ()2-s2.0-85157998944 (Scopus ID)
Available from: 2023-06-28 Created: 2023-06-28 Last updated: 2023-06-28Bibliographically approved
Bellm, E. C., Wang, Y., van Roestel, J., Phillipson, R. A., Coughlin, M. W., Tomsick, J. A., . . . Schwendeman, E. J. (2023). An Optically Discovered Outburst from XTE J1859+226. Astrophysical Journal, 956(1), Article ID 21.
Open this publication in new window or tab >>An Optically Discovered Outburst from XTE J1859+226
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2023 (English)In: Astrophysical Journal, ISSN 0004-637X, E-ISSN 1538-4357, Vol. 956, no 1, article id 21Article in journal (Refereed) Published
Abstract [en]

Using the Zwicky Transient Facility, in 2021 February we identified the first known outburst of the black hole X-ray transient XTE J1859+226 since its discovery in 1999. The outburst was visible at X-ray, UV, and optical wavelengths for less than 20 days, substantially shorter than its full outburst of 320 days in 1999, and the observed peak luminosity was 2 orders of magnitude lower. Its peak bolometric luminosity was only 2 × 1035 erg s−1, implying an Eddington fraction of about 3 × 10−4. The source remained in the hard spectral state throughout the outburst. From optical spectroscopy measurements we estimate an outer disk radius of 1011 cm. The low observed X-ray luminosity is not sufficient to irradiate the entire disk, but we observe a surprising exponential decline in the X-ray light curve. These observations highlight the potential of optical and infrared synoptic surveys to discover low-luminosity activity from X-ray transients.

National Category
Astronomy, Astrophysics and Cosmology
Identifiers
urn:nbn:se:su:diva-223856 (URN)10.3847/1538-4357/acf37c (DOI)001084046900001 ()2-s2.0-85175073085 (Scopus ID)
Available from: 2023-11-22 Created: 2023-11-22 Last updated: 2023-11-22Bibliographically approved
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ORCID iD: ORCID iD iconorcid.org/0000-0003-1546-6615

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