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Author Witte, S.; Villanueva-Domingo, P.; Gariazzo, S.; Mena, O.; Palomares-Ruiz, S. url  doi
openurl 
  Title EDGES result versus CMB and low-redshift constraints on ionization histories Type Journal Article
  Year 2018 Publication Physical Review D Abbreviated Journal Phys. Rev. D  
  Volume 97 Issue 10 Pages 103533 - 8pp  
  Keywords  
  Abstract We examine the results from the Experiment to Detect the Global Epoch of Reionization Signature (EDGES), which has recently claimed the detection of a strong absorption in the 21 cm hyperfine transition line of neutral hydrogen, at redshifts demarcating the early stages of star formation. More concretely, we study the compatibility of the shape of the EDGES absorption profile, centered at a redshift of z similar to 17.2, with measurements of the reionization optical depth, the Gunn-Peterson optical depth, and Lyman-alpha emission from star-forming galaxies, for a variety of possible reionization models within the standard ACDM framework (that is, a Universe with a cosmological constant. and cold dark matter CDM). When, conservatively, we only try to accommodate the location of the absorption dip, we identify a region in the parameter space of the astrophysical parameters that successfully explains all of the aforementioned observations. However, one of the most abnormal features of the EDGES measurement is the absorption amplitude, which is roughly a factor of 2 larger than the maximum allowed value in the ACDM framework. We point out that the simple considered astrophysical models that produce the largest absorption amplitudes are unable to explain the depth of the dip and of reproducing the observed shape of the absorption profile.  
  Address [Witte, Samuel; Villanueva-Domingo, Pablo; Gariazzo, Stefano; Mena, Olga; Palomares-Ruiz, Sergio] Univ Valencia, CSIC, Inst Fis Corpuscular IFIC, Apartado Correos 22085, E-46071 Valencia, Spain  
  Corporate Author Thesis  
  Publisher (up) Amer Physical Soc Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 2470-0010 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000433291600010 Approved no  
  Is ISI yes International Collaboration no  
  Call Number IFIC @ pastor @ Serial 3606  
Permanent link to this record
 

 
Author Caputo, A.; Pena-Garay, C.; Witte, S.J. url  doi
openurl 
  Title Looking for axion dark matter in dwarf spheroidal galaxies Type Journal Article
  Year 2018 Publication Physical Review D Abbreviated Journal Phys. Rev. D  
  Volume 98 Issue 8 Pages 083024 - 6pp  
  Keywords  
  Abstract We study the extent to which the decay of cold dark matter axions can be probed with forthcoming radio telescopes such as the Square Kilometer Array (SKA). In particular, we focus on signals arising from dwarf spheroidal galaxies, where astrophysical uncertainties are reduced and the expected magnetic field strengths are such that signals arising from axion decay may dominate over axion-photon conversion in a magnetic field. We show that with similar to 100 hr of observing time, SKA could improve current sensitivity by 2-3 orders of magnitude-potentially obtaining sufficient sensitivity to begin probing the decay of cold dark matter axions.  
  Address [Caputo, Andrea; Witte, Samuel J.] Univ Valencia, CSIC, Inst Fis Corpuscular IFIC, Apartado Correos 22085, E-46071 Valencia, Spain  
  Corporate Author Thesis  
  Publisher (up) Amer Physical Soc Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 2470-0010 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000448458600001 Approved no  
  Is ISI yes International Collaboration no  
  Call Number IFIC @ pastor @ Serial 3788  
Permanent link to this record
 

 
Author Gelmini, G.B.; Takhistov, V.; Witte, S.J. url  doi
openurl 
  Title Geoneutrinos in large direct detection experiments Type Journal Article
  Year 2019 Publication Physical Review D Abbreviated Journal Phys. Rev. D  
  Volume 99 Issue 9 Pages 093009 - 11pp  
  Keywords  
  Abstract Geoneutrinos can provide a unique insight into Earth's interior, its central engine, and its formation history. We study the detection of geoneutrinos in large direct detection experiments, which has been considered nonfeasible. We compute the geoneutrino-induced electron and nuclear recoil spectra in different materials, under several optimistic assumptions. We identify germanium as the most promising target element due to the low nuclear recoil energy threshold that could be achieved. The minimum exposure required for detection would be O(10) ton-years. The realistic low thresholds achievable in germanium and silicon permit the detection of K-40 geoneutrinos. These are particularly important to determining Earth's formation history, but they are below the kinematic threshold of inverse beta decay, the detection process used in scintillator-based experiments.  
  Address [Gelmini, Graciela B.; Takhistov, Volodymyr] Univ Calif Los Angeles, Dept Phys & Astron, Los Angeles, CA 90095 USA, Email: gelmini@physics.ucla.edu;  
  Corporate Author Thesis  
  Publisher (up) Amer Physical Soc Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 2470-0010 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000469022000001 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 4024  
Permanent link to this record
 

 
Author Mena, O.; Palomares-Ruiz, S.; Villanueva-Domingo, P.; Witte, S.J. url  doi
openurl 
  Title Constraining the primordial black hole abundance with 21-cm cosmology Type Journal Article
  Year 2019 Publication Physical Review D Abbreviated Journal Phys. Rev. D  
  Volume 100 Issue 4 Pages 043540 - 23pp  
  Keywords  
  Abstract The discoveries of a number of binary black hole mergers by LIGO and VIRGO have reinvigorated the interest that primordial black holes (PBHs) of tens of solar masses could contribute non-negligibly to the dark matter energy density. Should even a small population of PBHs with masses greater than or similar to O(M-circle dot) exist, they could profoundly impact the properties of the intergalactic medium and provide insight into novel processes at work in the early Universe. We demonstrate here that observations of the 21-cm transition in neutral hydrogen during the epochs of reionization and cosmic dawn will likely provide one of the most stringent tests of solar mass PBHs. In the context of 21-cm cosmology, PBHs give rise to three distinct observable effects: (i) the modification to the primordial power spectrum (and thus also the halo mass function) induced by Poisson noise, (ii) a uniform heating and ionization of the intergalactic medium via x-rays produced during accretion, and (iii) a local modification to the temperature and density of the ambient medium surrounding isolated PBHs. Using a four-parameter astrophysical model, we show that experiments like SKA and HERA could potentially improve upon existing constraints derived using observations of the cosmic microwave background by more than 1 order of magnitude.  
  Address [Mena, Olga; Palomares-Ruiz, Sergio; Villanueva-Domingo, Pablo; Witte, Samuel J.] Univ Valencia, CSIC, Inst Fis Corpuscular IFIC, Apartado Correos 22085, E-46071 Valencia, Spain  
  Corporate Author Thesis  
  Publisher (up) Amer Physical Soc Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 2470-0010 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000483047300003 Approved no  
  Is ISI yes International Collaboration no  
  Call Number IFIC @ pastor @ Serial 4122  
Permanent link to this record
 

 
Author Raj, N.; Takhistov, V.; Witte, S.J. url  doi
openurl 
  Title Presupernova neutrinos in large dark matter direct detection experiments Type Journal Article
  Year 2020 Publication Physical Review D Abbreviated Journal Phys. Rev. D  
  Volume 101 Issue 4 Pages 043008 - 10pp  
  Keywords  
  Abstract The next Galactic core-collapse supernova (SN) is a highly anticipated observational target for neutrino telescopes. However, even prior to collapse, massive dying stars shine copiously in “pre-supernova” (pre-SN) neutrinos, which can potentially act as efficient SN warning alarms and provide novel information about the very last stages of stellar evolution. We explore the sensitivity to pre-SN neutrinos of large-scale direct dark matter detection experiments, which, unlike dedicated neutrino telescopes, take full advantage of coherent neutrino-nucleus scattering. We find that argon-based detectors with target masses of O(100)tons (i.e., comparable in size to the proposed ARGO experiment) operating at sub-keV thresholds can detect O(10-100) pre-SN neutrinos coming from a source at a characteristic distance of similar to 200 pc, such as Betelgeuse (alpha Orionis). Large-scale xenon-based experiments with similarly low thresholds could also be sensitive to pre-SN neutrinos. For a Betelgeuse-type source, large-scale dark matter experiments could provide a SN warning siren similar to 10 hours prior to the explosion. We also comment on the complementarity of large-scale direct dark matter detection experiments and neutrino telescopes in the understanding of core-collapse SN.  
  Address [Raj, Nirmal] TRIUMF, 4004 Wesbrook Mall, Vancouver, BC V6T 2A3, Canada, Email: nraj@triumf.ca;  
  Corporate Author Thesis  
  Publisher (up) Amer Physical Soc Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 2470-0010 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000513575900001 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 4285  
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