Science with the Ultraviolet Explorer (UVEX)

Kulkarni, S. R.; Harrison, Fiona A.; Grefenstette, Brian W.; Earnshaw, Hannah P.; Andreoni, Igor; Berg, Danielle A.; Bloom, J.; Cenko, S. Bradley; Chornock, R.; Christiansen, Jessie L.; Coughlin, M. W.; Criswell, A. W.; Darvish, Behnam; Das, Kaustav K.; De, Kishalay; Dixon, Don; Dorsman, Bas; El-Badry, Kareem; Evans, Christopher J.; Ford, K. E. Saavik; Fremling, Christoffer; Gänsicke, B. T.; Gezari, Suvi; Götberg, Y.; Green, Gregory; Graham, M. J.; Heida, Marianne; Ho, Anna Y. Q.; Jaodand, Amruta; Johns–Krull, Christopher M.; Kasliwal, Mansi M.; Lazzarini, Margaret; Lu, W.; Margutti, R.; Martin, D. Christopher; Masters, D. C.; McKernan, Barry; Nissanke, S.; Parazin, B.; Perley, D.; Phinney, E. S.; Piro, Anthony L.; Raaijmakers, G.; Rodriguez, Antonio C.; Senchyna, Peter; Singer, L. P.; Spake, Jessica; Stassun, Keivan G.; Stern, Daniel; Teplitz, Harry I.; Weisz, Daniel R.; Yao, Yuhan

doi:10.48550/arxiv.2111.15608

Cited by 41 publications

(39 citation statements)

References 408 publications

(493 reference statements)

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“…Fig. 2 of [88]), further increasing the amelioration factor needed to obtain f PBH ∼ 1 at M = 10 22 g. Thus, we conclude that the window for all DM into PBHs cannot be closed by direct photon de-tection from PBH evaporation. 11 Complementary constraints, relying on complex modelling, are thus needed: dynamical capture by or microlensing of stars (see the review by [90]), rare collisions with solid objects [91] or GRB lensing [92].…”

Section: F Very Low Energiesmentioning

confidence: 73%

“…GC) component of the background. The GALEX [87] (and future UVEX [88]) instruments are sensitive only starting above λ ∼ 1000 Å. Suppose that we extrapolate the "ideal" instrument capabilities, the PBH Hawking radiation rates and the GC+EXRB background down to the eV energy scale: dΦ bckg /dE ∝ E −2 and A eff (E) = A eff (E) at E = 10 − 1000 eV.…”

Section: F Very Low Energiesmentioning

confidence: 99%

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Limits on primordial black holes detectability with Isatis: A BlackHawk tool

Auffinger

2022

Preprint

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Primordial black holes (PBHs) are convenient candidates to explain the elusive dark matter (DM). However, years of constraints from various astronomical observations have constrained their abundance over a wide range of masses, leaving only a narrow window open at 10 17 g M 10 22 g for all DM in the form of PBHs. We reexamine this disputed window with a critical eye, interrogating the general hypotheses underlying the direct photon constraints. We review 4 levels of assumptions: i) instrument characteristics, ii) prediction of the (extra)galactic photon flux, iii) statistical method of signal-to-data comparison and iv) computation of the Hawking radiation rate. Thanks to Isatis, a new tool designed for the public Hawking radiation code BlackHawk, we first revisit the existing and prospective constraints on the PBH abundance and investigate the impact of assumptions i)-iv). We show that the constraints can vary by several orders of magnitude, advocating the necessity of a reduction of the theoretical sources of uncertainties. Second, we consider an "ideal" instrument and we demonstrate that the PBH DM scenario can only be constrained by the direct photon Hawking radiation phenomenon below Mmax ∼ 10 20 g. The upper part of the mass window should therefore be closed by other means.

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Section: F Very Low Energiesmentioning

confidence: 73%

Section: F Very Low Energiesmentioning

confidence: 99%

Limits on primordial black holes detectability with Isatis: A BlackHawk tool

Auffinger

2022

Preprint

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“…Joint modeling of bloated and sdOB companions to Be stars -many more of which will be within the reach of proposed future missions (e.g. Jones et al 2021;Kulkarni et al 2021) -will continue to solidify our understanding of the importance of mass transfer in the formation of Be stars.…”

Section: Discussionmentioning

confidence: 97%

Birth of a Be star: an APOGEE search for Be stars forming through binary mass transfer

El-Badry¹,

Conroy²,

Quataert³

et al. 2022

Preprint

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Motivated by recent suggestions that many Be stars form through binary mass transfer, we searched the APOGEE survey for Be stars with bloated, stripped companions. From a well-defined parent sample of 297 Be stars, we identified one mass-transfer binary, HD 15124. The object consists of a main-sequence Be star (𝑀 Be = 5.3 ± 0.6 𝑀 ) with a low-mass (𝑀 donor = 0.92 ± 0.22 𝑀 ), subgiant companion on a 5.47-day orbit. The emission lines originate in an accretion disk caused by ongoing mass transfer, not from a decretion disk as in classical Be stars. Both stars have surface abundances bearing imprint of CNO processing in the donor's core: the surface helium fraction is 𝑌 He ≈ 0.6, and the nitrogen-to-carbon ratio is 1000 times the solar value. The system's properties are well-matched by binary evolution models in which mass transfer begins while a 3 − 5 𝑀 donor leaves the main sequence, with the secondary becoming the Be star. These models predict that the system will soon become a detached Be + stripped star binary like HR 6819 and LB-1, with the stripped donor eventually contracting to become a core helium-burning sdOB star. Discovery of one object in this short-lived (∼1 Myr) evolutionary phase implies the existence of many more that have already passed through it and are now Be + sdOB binaries. We infer that (28 +27 −16 ) % of Be stars have stripped companions, most of which are faint. Together with the dearth of main-sequence companions to Be stars and recent discovery of numerous Be + sdOB binaries in the UV, our results imply that binarity plays an important role in the formation of Be stars.

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“…However, there are no large UV surveying facilities currently in operation, though some are planned or proposed (see e.g. ULTRASAT, Sagiv et al 2014;CASTOR, Côte et al 2012;Dorado, Singer et al 2021; UVEX, Kulkarni et al 2021). See Kulkarni et al (2021) for a review of past and future missions with UV-transient searching capabilities.…”

Section: Introductionmentioning

confidence: 99%

“…ULTRASAT, Sagiv et al 2014;CASTOR, Côte et al 2012;Dorado, Singer et al 2021; UVEX, Kulkarni et al 2021). See Kulkarni et al (2021) for a review of past and future missions with UV-transient searching capabilities.…”

Section: Introductionmentioning

confidence: 99%

TUVOpipe: a pipeline to search for UV transients with Swift-UVOT

Modiano,

Wijnands,

Parikh

et al. 2022

Preprint

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Despite the prevalence of transient-searching facilities operating across most wavelengths, the ultraviolet (UV) transient sky remains to be systematically studied. Therefore, we have recently initiated the Transient Ultraviolet Objects (TUVO) project, with which we search for serendipitous UV transients in data obtained using currently available UV instruments with a strong focus on the UV/Optical (UVOT) telescope aboard the Neil Gehrels Swift Observatory (an overview of the project is described in a companion paper). Here we describe the pipeline (named TUVOpipe) we constructed in order to find such transients in the UVOT data, using difference image analysis. The pipeline is run daily on all new public UVOT data (which are available 6-8 hours after the observations are performed), so we discover transients in near real-time. Transients which last >0.5 days are therefore still active when discovered, allowing for follow-up observations to be performed. From October 1, 2020, to the time of submission, using TUVOpipe we have processed 111 330 individual UVOT images and we currently detect an average rate of ∼100 transient candidates per day. Of these daily candidates, on average ∼30% are real transients (separated by human vetting from the remaining 'bogus' transients which were not discarded automatically within the pipeline). Most of the real transients correspond to known variable stars, though we also detect a significant number of known active galactic nuclei and accreting white dwarfs. TUVOpipe can additionally run in archival mode, whereby all the archival UVOT data of a given field is scoured for 'historical' transients; in this mode we also mostly find variable stars. However, some of the transients we find (in particular in the real-time mode) represent previously unreported new transients, or undiscovered outbursts of previously known transients, predominantly outbursts from cataclysmic variables. In this paper we describe the operation of (both modes of) TUVOpipe and some of the initial results we have so far obtained.

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Science with the Ultraviolet Explorer (UVEX)

Cited by 41 publications

References 408 publications

Limits on primordial black holes detectability with Isatis: A BlackHawk tool

Limits on primordial black holes detectability with Isatis: A BlackHawk tool

Birth of a Be star: an APOGEE search for Be stars forming through binary mass transfer

TUVOpipe: a pipeline to search for UV transients with Swift-UVOT

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