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7 results on '"Golkhou, V.Z."'

1. Seventeen Tidal Disruption Events from the First Half of ZTF Survey Observations: Entering a New Era of Population Studies

Author

Velzen, S. van, Gezari, S., Hammerstein, E., Roth, N., Frederick, S., Ward, C., Hung, T., Cenko, S.B., Stein, R., Perley, D.A., Taggart, K., Foley, R.J., Sollerman, J., Blagorodnova, N., Andreoni, I., Bellm, E.C., Brinnel, V., De, K., Dekany, R., Feeney, M., Fremling, C., Giomi, M., Golkhou, V.Z., Graham, M.J., Ho, A.Y.Q., Kasliwal, M.M., Kilpatrick, C.D., Kulkarni, S.R., Kupfer, T., Laher, R.R., Mahabal, A., Masci, F.J., Miller, A.A., Nordin, J., Riddle, R., Rusholme, B., Santen, J.v., Sharma, Y., Shupe, D.L., Soumagnac, M.T., Velzen, S. van, Gezari, S., Hammerstein, E., Roth, N., Frederick, S., Ward, C., Hung, T., Cenko, S.B., Stein, R., Perley, D.A., Taggart, K., Foley, R.J., Sollerman, J., Blagorodnova, N., Andreoni, I., Bellm, E.C., Brinnel, V., De, K., Dekany, R., Feeney, M., Fremling, C., Giomi, M., Golkhou, V.Z., Graham, M.J., Ho, A.Y.Q., Kasliwal, M.M., Kilpatrick, C.D., Kulkarni, S.R., Kupfer, T., Laher, R.R., Mahabal, A., Masci, F.J., Miller, A.A., Nordin, J., Riddle, R., Rusholme, B., Santen, J.v., Sharma, Y., Shupe, D.L., and Soumagnac, M.T.

Abstract

Contains fulltext : 230757.pdf (publisher's version ) (Closed access) Contains fulltext : 230757pre.pdf (preprint version ) (Open Access)

Published
2021

2. Seventeen Tidal Disruption Events from the First Half of ZTF Survey Observations: Entering a New Era of Population Studies

Author

Velzen, S. van, Gezari, S., Hammerstein, E., Roth, N., Frederick, S., Ward, C., Hung, T., Cenko, S.B., Stein, R., Perley, D.A., Taggart, K., Foley, R.J., Sollerman, J., Blagorodnova, N., Andreoni, I., Bellm, E.C., Brinnel, V., De, K., Dekany, R., Feeney, M., Fremling, C., Giomi, M., Golkhou, V.Z., Graham, M.J., Ho, A.Y.Q., Kasliwal, M.M., Kilpatrick, C.D., Kulkarni, S.R., Kupfer, T., Laher, R.R., Mahabal, A., Masci, F.J., Miller, A.A., Nordin, J., Riddle, R., Rusholme, B., Santen, J.v., Sharma, Y., Shupe, D.L., Soumagnac, M.T., Velzen, S. van, Gezari, S., Hammerstein, E., Roth, N., Frederick, S., Ward, C., Hung, T., Cenko, S.B., Stein, R., Perley, D.A., Taggart, K., Foley, R.J., Sollerman, J., Blagorodnova, N., Andreoni, I., Bellm, E.C., Brinnel, V., De, K., Dekany, R., Feeney, M., Fremling, C., Giomi, M., Golkhou, V.Z., Graham, M.J., Ho, A.Y.Q., Kasliwal, M.M., Kilpatrick, C.D., Kulkarni, S.R., Kupfer, T., Laher, R.R., Mahabal, A., Masci, F.J., Miller, A.A., Nordin, J., Riddle, R., Rusholme, B., Santen, J.v., Sharma, Y., Shupe, D.L., and Soumagnac, M.T.

Abstract

Contains fulltext : 230757.pdf (publisher's version ) (Closed access) Contains fulltext : 230757pre.pdf (preprint version ) (Open Access)

Published
2021

3. A tidal disruption event coincident with a high-energy neutrino

Author

Stein, R., Velzen, S.V., Kowalski, M., Franckowiak, A., Gezari, S., Miller-Jones, James, Frederick, S., Sfaradi, I., Bietenholz, M.F., Horesh, A., Fender, R., Garrappa, S., Ahumada, T., Andreoni, I., Belicki, J., Bellm, E.C., Böttcher, M., Brinnel, V., Burruss, R., Cenko, S.B., Coughlin, M.W., Cunningham, V., Drake, A., Farrar, G.R., Feeney, M., Foley, R.J., Gal-Yam, A., Golkhou, V.Z., Goobar, A., Graham, M.J., Hammerstein, E., Helou, G., Hung, T., Kasliwal, M.M., Kilpatrick, C.D., Kong, A.K.H., Kupfer, T., Laher, R.R., Mahabal, A.A., Masci, F.J., Necker, J., Nordin, J., Perley, D.A., Rigault, M., Reusch, S., Rodriguez, H., Rojas-Bravo, C., Rusholme, B., Shupe, D.L., Singer, L.P., Sollerman, J., Soumagnac, M.T., Stern, D., Taggart, K., van Santen, J., Ward, C., Woudt, P., Yao, Y., Stein, R., Velzen, S.V., Kowalski, M., Franckowiak, A., Gezari, S., Miller-Jones, James, Frederick, S., Sfaradi, I., Bietenholz, M.F., Horesh, A., Fender, R., Garrappa, S., Ahumada, T., Andreoni, I., Belicki, J., Bellm, E.C., Böttcher, M., Brinnel, V., Burruss, R., Cenko, S.B., Coughlin, M.W., Cunningham, V., Drake, A., Farrar, G.R., Feeney, M., Foley, R.J., Gal-Yam, A., Golkhou, V.Z., Goobar, A., Graham, M.J., Hammerstein, E., Helou, G., Hung, T., Kasliwal, M.M., Kilpatrick, C.D., Kong, A.K.H., Kupfer, T., Laher, R.R., Mahabal, A.A., Masci, F.J., Necker, J., Nordin, J., Perley, D.A., Rigault, M., Reusch, S., Rodriguez, H., Rojas-Bravo, C., Rusholme, B., Shupe, D.L., Singer, L.P., Sollerman, J., Soumagnac, M.T., Stern, D., Taggart, K., van Santen, J., Ward, C., Woudt, P., and Yao, Y.

Abstract

Cosmic neutrinos provide a unique window into the otherwise hidden mechanism of particle acceleration in astrophysical objects. The IceCube Collaboration recently reported the likely association of one high-energy neutrino with a flare from the relativistic jet of an active galaxy pointed towards the Earth. However a combined analysis of many similar active galaxies revealed no excess from the broader population, leaving the vast majority of the cosmic neutrino flux unexplained. Here we present the likely association of a radio-emitting tidal disruption event, AT2019dsg, with a second high-energy neutrino. AT2019dsg was identified as part of our systematic search for optical counterparts to high-energy neutrinos with the Zwicky Transient Facility. The probability of finding any coincident radio-emitting tidal disruption event by chance is 0.5%, while the probability of finding one as bright in bolometric energy flux as AT2019dsg is 0.2%. Our electromagnetic observations can be explained through a multizone model, with radio analysis revealing a central engine, embedded in a UV photosphere, that powers an extended synchrotron-emitting outflow. This provides an ideal site for petaelectronvolt neutrino production. Assuming that the association is genuine, our observations suggest that tidal disruption events with mildly relativistic outflows contribute to the cosmic neutrino flux.

Published
2021

4. ZTF18aalrxas: A Type IIb Supernova from a Very Extended Low-mass Progenitor

Author

Fremling, C., Ko, H., Dugas, A., Ergon, M., Sollerman, J., Bagdasaryan, A., Barbarino, C., Belicki, J., Bellm, E., Blagorodnova, N., De, K., Dekany, R., Frederick, S., Gal-Yam, A., Goldstein, D.A., Golkhou, V.Z., Graham, M., Kasliwal, M., Kowalski, M., Kulkarni, S.R., Kupfer, T., Laher, R.R., Masci, F.J., Miller, A.A., Neill, J.D., Perley, D.A., Rebbapragada, U.D., Riddle, R., Rusholme, B., Schulze, S., Smith, R.M., Tartaglia, L., Yan, L., Yao, Y., Fremling, C., Ko, H., Dugas, A., Ergon, M., Sollerman, J., Bagdasaryan, A., Barbarino, C., Belicki, J., Bellm, E., Blagorodnova, N., De, K., Dekany, R., Frederick, S., Gal-Yam, A., Goldstein, D.A., Golkhou, V.Z., Graham, M., Kasliwal, M., Kowalski, M., Kulkarni, S.R., Kupfer, T., Laher, R.R., Masci, F.J., Miller, A.A., Neill, J.D., Perley, D.A., Rebbapragada, U.D., Riddle, R., Rusholme, B., Schulze, S., Smith, R.M., Tartaglia, L., Yan, L., and Yao, Y.

Abstract

Contains fulltext : 204340.pdf (publisher's version ) (Open Access) Contains fulltext : 204340-1.pdf (preprint version ) (Open Access), We investigate ZTF18aalrxas, a double-peaked Type IIb core-collapse supernova (SN) discovered during science validation of the Zwicky Transient Facility. ZTF18aalrxas was discovered while the optical emission was still rising toward the initial cooling peak (0.7 mag over 2 days). Our observations consist of multi-band (ultraviolet and optical) light curves (LCs), and optical spectra spanning from ≈0.7 to ≈180 days past the explosion. We use a Monte-Carlo based non-local thermodynamic equilibrium model that simultaneously reproduces both the 56Ni-powered bolometric LC and our nebular spectrum. This model is used to constrain the synthesized radioactive nickel mass (0.17 M ☉) and the total ejecta mass (1.7 M ☉) of the SN. The cooling emission is modeled using semi-analytical extended envelope models to constrain the progenitor radius (790–1050 R ⊙) at the time of explosion. Our nebular spectrum shows signs of interaction with a dense circumstellar medium (CSM), and this spectrum is modeled and analyzed to constrain the amount of ejected oxygen (0.3–0.5 M ☉) and the total hydrogen mass (≈0.15 M ☉) in the envelope of the progenitor. The oxygen mass of ZTF18aalrxas is consistent with a low (12–13 M ☉) zero-age main-sequence mass progenitor. The LCs and spectra of ZTF18aalrxas are not consistent with massive single-star SN Type IIb progenitor models. The presence of an extended hydrogen envelope of low mass, the presence of a dense CSM, the derived ejecta mass, and the late-time oxygen emission can all be explained in a binary model scenario.

Published
2019

5. ZTF18aalrxas: A Type IIb Supernova from a Very Extended Low-mass Progenitor

Author

Fremling, C., Ko, H., Dugas, A., Ergon, M., Sollerman, J., Bagdasaryan, A., Barbarino, C., Belicki, J., Bellm, E., Blagorodnova, N., De, K., Dekany, R., Frederick, S., Gal-Yam, A., Goldstein, D.A., Golkhou, V.Z., Graham, M., Kasliwal, M., Kowalski, M., Kulkarni, S.R., Kupfer, T., Laher, R.R., Masci, F.J., Miller, A.A., Neill, J.D., Perley, D.A., Rebbapragada, U.D., Riddle, R., Rusholme, B., Schulze, S., Smith, R.M., Tartaglia, L., Yan, L., Yao, Y., Fremling, C., Ko, H., Dugas, A., Ergon, M., Sollerman, J., Bagdasaryan, A., Barbarino, C., Belicki, J., Bellm, E., Blagorodnova, N., De, K., Dekany, R., Frederick, S., Gal-Yam, A., Goldstein, D.A., Golkhou, V.Z., Graham, M., Kasliwal, M., Kowalski, M., Kulkarni, S.R., Kupfer, T., Laher, R.R., Masci, F.J., Miller, A.A., Neill, J.D., Perley, D.A., Rebbapragada, U.D., Riddle, R., Rusholme, B., Schulze, S., Smith, R.M., Tartaglia, L., Yan, L., and Yao, Y.

Abstract

Contains fulltext : 204340.pdf (publisher's version ) (Open Access) Contains fulltext : 204340-1.pdf (preprint version ) (Open Access), We investigate ZTF18aalrxas, a double-peaked Type IIb core-collapse supernova (SN) discovered during science validation of the Zwicky Transient Facility. ZTF18aalrxas was discovered while the optical emission was still rising toward the initial cooling peak (0.7 mag over 2 days). Our observations consist of multi-band (ultraviolet and optical) light curves (LCs), and optical spectra spanning from ≈0.7 to ≈180 days past the explosion. We use a Monte-Carlo based non-local thermodynamic equilibrium model that simultaneously reproduces both the 56Ni-powered bolometric LC and our nebular spectrum. This model is used to constrain the synthesized radioactive nickel mass (0.17 M ☉) and the total ejecta mass (1.7 M ☉) of the SN. The cooling emission is modeled using semi-analytical extended envelope models to constrain the progenitor radius (790–1050 R ⊙) at the time of explosion. Our nebular spectrum shows signs of interaction with a dense circumstellar medium (CSM), and this spectrum is modeled and analyzed to constrain the amount of ejected oxygen (0.3–0.5 M ☉) and the total hydrogen mass (≈0.15 M ☉) in the envelope of the progenitor. The oxygen mass of ZTF18aalrxas is consistent with a low (12–13 M ☉) zero-age main-sequence mass progenitor. The LCs and spectra of ZTF18aalrxas are not consistent with massive single-star SN Type IIb progenitor models. The presence of an extended hydrogen envelope of low mass, the presence of a dense CSM, the derived ejecta mass, and the late-time oxygen emission can all be explained in a binary model scenario.

Published
2019

6. ZTF18aalrxas: A Type IIb Supernova from a Very Extended Low-mass Progenitor

Author

Fremling, C., Ko, H., Dugas, A., Ergon, M., Sollerman, J., Bagdasaryan, A., Barbarino, C., Belicki, J., Bellm, E., Blagorodnova, N., De, K., Dekany, R., Frederick, S., Gal-Yam, A., Goldstein, D.A., Golkhou, V.Z., Graham, M., Kasliwal, M., Kowalski, M., Kulkarni, S.R., Kupfer, T., Laher, R.R., Masci, F.J., Miller, A.A., Neill, J.D., Perley, D.A., Rebbapragada, U.D., Riddle, R., Rusholme, B., Schulze, S., Smith, R.M., Tartaglia, L., Yan, L., Yao, Y., Fremling, C., Ko, H., Dugas, A., Ergon, M., Sollerman, J., Bagdasaryan, A., Barbarino, C., Belicki, J., Bellm, E., Blagorodnova, N., De, K., Dekany, R., Frederick, S., Gal-Yam, A., Goldstein, D.A., Golkhou, V.Z., Graham, M., Kasliwal, M., Kowalski, M., Kulkarni, S.R., Kupfer, T., Laher, R.R., Masci, F.J., Miller, A.A., Neill, J.D., Perley, D.A., Rebbapragada, U.D., Riddle, R., Rusholme, B., Schulze, S., Smith, R.M., Tartaglia, L., Yan, L., and Yao, Y.

Abstract

Contains fulltext : 204340.pdf (publisher's version ) (Open Access) Contains fulltext : 204340-1.pdf (preprint version ) (Open Access), We investigate ZTF18aalrxas, a double-peaked Type IIb core-collapse supernova (SN) discovered during science validation of the Zwicky Transient Facility. ZTF18aalrxas was discovered while the optical emission was still rising toward the initial cooling peak (0.7 mag over 2 days). Our observations consist of multi-band (ultraviolet and optical) light curves (LCs), and optical spectra spanning from ≈0.7 to ≈180 days past the explosion. We use a Monte-Carlo based non-local thermodynamic equilibrium model that simultaneously reproduces both the 56Ni-powered bolometric LC and our nebular spectrum. This model is used to constrain the synthesized radioactive nickel mass (0.17 M ☉) and the total ejecta mass (1.7 M ☉) of the SN. The cooling emission is modeled using semi-analytical extended envelope models to constrain the progenitor radius (790–1050 R ⊙) at the time of explosion. Our nebular spectrum shows signs of interaction with a dense circumstellar medium (CSM), and this spectrum is modeled and analyzed to constrain the amount of ejected oxygen (0.3–0.5 M ☉) and the total hydrogen mass (≈0.15 M ☉) in the envelope of the progenitor. The oxygen mass of ZTF18aalrxas is consistent with a low (12–13 M ☉) zero-age main-sequence mass progenitor. The LCs and spectra of ZTF18aalrxas are not consistent with massive single-star SN Type IIb progenitor models. The presence of an extended hydrogen envelope of low mass, the presence of a dense CSM, the derived ejecta mass, and the late-time oxygen emission can all be explained in a binary model scenario.

Published
2019

7. The First Tidal Disruption Flare in ZTF: From Photometric Selection to Multi-wavelength Characterization

Author

Van Velzen, S., Gezari, S., Cenko, S.B., Kara, E., Miller-Jones, James, Hung, T., Bright, J., Roth, N., Blagorodnova, N., Huppenkothen, D., Yan, L., Ofek, E., Sollerman, J., Frederick, S., Ward, C., Graham, M.J., Fender, R., Kasliwal, M.M., Canella, C., Stein, R., Giomi, M., Brinnel, V., Santen, J.V., Nordin, J., Bellm, E.C., Dekany, R., Fremling, C., Golkhou, V.Z., Kupfer, T., Kulkarni, S.R., Laher, R.R., Mahabal, A., Masci, F.J., Miller, A.A., Neill, J.D., Riddle, R., Rigault, M., Rusholme, B., Soumagnac, M.T., Tachibana, Y., Van Velzen, S., Gezari, S., Cenko, S.B., Kara, E., Miller-Jones, James, Hung, T., Bright, J., Roth, N., Blagorodnova, N., Huppenkothen, D., Yan, L., Ofek, E., Sollerman, J., Frederick, S., Ward, C., Graham, M.J., Fender, R., Kasliwal, M.M., Canella, C., Stein, R., Giomi, M., Brinnel, V., Santen, J.V., Nordin, J., Bellm, E.C., Dekany, R., Fremling, C., Golkhou, V.Z., Kupfer, T., Kulkarni, S.R., Laher, R.R., Mahabal, A., Masci, F.J., Miller, A.A., Neill, J.D., Riddle, R., Rigault, M., Rusholme, B., Soumagnac, M.T., and Tachibana, Y.

Abstract

© 2019. The American Astronomical Society. All rights reserved.. We present Zwicky Transient Facility (ZTF) observations of the tidal disruption flare AT2018zr/PS18kh reported by Holoien et al. and detected during ZTF commissioning. The ZTF light curve of the tidal disruption event (TDE) samples the rise-to-peak exceptionally well, with 50 days of g- and r-band detections before the time of maximum light. We also present our multi-wavelength follow-up observations, including the detection of a thermal (kT ≈ 100 eV) X-ray source that is two orders of magnitude fainter than the contemporaneous optical/UV blackbody luminosity, and a stringent upper limit to the radio emission. We use observations of 128 known active galactic nuclei (AGNs) to assess the quality of the ZTF astrometry, finding a median host-flare distance of 0.″2 for genuine nuclear flares. Using ZTF observations of variability from known AGNs and supernovae we show how these sources can be separated from TDEs. A combination of light-curve shape, color, and location in the host galaxy can be used to select a clean TDE sample from multi-band optical surveys such as ZTF or the Large Synoptic Survey Telescope.

Published
2019

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