Nicole Crumpler - Academia.edu (original) (raw)
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Homi Bhabha National Institute (HBNI, BARC, MUMBAI)
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Papers by Nicole Crumpler
Physical Review D
We constrain a broad class of "hairy" black hole models capable of directly sourcing electromagne... more We constrain a broad class of "hairy" black hole models capable of directly sourcing electromagnetic radiation during a binary black hole merger. This signal is generic and model-independent since it is characterized by the black hole mass (M) and the fraction of that mass released as radiation (ϵ). For field energy densities surpassing the Schwinger limit, this mechanism triggers pair production to produce a gamma-ray burst. By cross-referencing gravitational wave events with gamma-ray observations, we place upper bounds of ϵ < 10 −5-10 −4 for 10-50M ⊙ black holes depending on the black hole mass. We discuss the weak detection of a gamma-ray burst following GW150914 and show that this event is consistent with rapid electromagnetic emission directly from a hairy black hole with ϵ ∼ 10 −7-10 −6. Below the Schwinger limit, ambient charged particles are rapidly accelerated to nearly the speed of light by the strong electromagnetic field. For 1-50M ⊙ black holes and ϵ ranging from 10 −20 to 10 −7 , the typical proton energies are ∼20 GeV-20 TeV and electron energies are ∼0.01-10 GeV. At these energies, cosmic ray protons and electrons quickly diffuse into the Milky Way's background magnetic field, making it difficult to identify a point source producing them. Overall, constraining ϵ in this less energetic regime becomes difficult and future constraints may need to consider specific models of hairy black holes.
The astronomer's telegram, Aug 1, 2019
The Astrophysical Journal, 2020
The effect of progenitor metallicity on Type Ia supernovae (SNe Ia) has important cosmological im... more The effect of progenitor metallicity on Type Ia supernovae (SNe Ia) has important cosmological implications due to the need for these standardizable candles to be compared across large spans of cosmic time in which the progenitor stars might have different properties. Theoretical models have come to different conclusions as to the wavelength range impacted by metallicity differences, leading to differing interpretations of the growing sample of UV observations. Recent work has claimed a correlation between the mid-UV flux of SNe Ia measured from Swift grism spectra and the gas-phase metallicities measured for their host galaxies. Here we examine UV photometry for the same objects. We find no significant correlations between the UV-optical colors (or UV/optical count rate ratios) of the SNe Ia and the host-galaxy properties of mass or metallicity. The lack of a significant correlation with host-galaxy metallicity implies that a physical difference other than progenitor metallicity dominates the UV flux differences. Understanding the existing observations requires improved theoretical models and a larger parameter space of physical differences.
Physical Review D
We constrain a broad class of "hairy" black hole models capable of directly sourcing electromagne... more We constrain a broad class of "hairy" black hole models capable of directly sourcing electromagnetic radiation during a binary black hole merger. This signal is generic and model-independent since it is characterized by the black hole mass (M) and the fraction of that mass released as radiation (ϵ). For field energy densities surpassing the Schwinger limit, this mechanism triggers pair production to produce a gamma-ray burst. By cross-referencing gravitational wave events with gamma-ray observations, we place upper bounds of ϵ < 10 −5-10 −4 for 10-50M ⊙ black holes depending on the black hole mass. We discuss the weak detection of a gamma-ray burst following GW150914 and show that this event is consistent with rapid electromagnetic emission directly from a hairy black hole with ϵ ∼ 10 −7-10 −6. Below the Schwinger limit, ambient charged particles are rapidly accelerated to nearly the speed of light by the strong electromagnetic field. For 1-50M ⊙ black holes and ϵ ranging from 10 −20 to 10 −7 , the typical proton energies are ∼20 GeV-20 TeV and electron energies are ∼0.01-10 GeV. At these energies, cosmic ray protons and electrons quickly diffuse into the Milky Way's background magnetic field, making it difficult to identify a point source producing them. Overall, constraining ϵ in this less energetic regime becomes difficult and future constraints may need to consider specific models of hairy black holes.
The astronomer's telegram, Aug 1, 2019
The Astrophysical Journal, 2020
The effect of progenitor metallicity on Type Ia supernovae (SNe Ia) has important cosmological im... more The effect of progenitor metallicity on Type Ia supernovae (SNe Ia) has important cosmological implications due to the need for these standardizable candles to be compared across large spans of cosmic time in which the progenitor stars might have different properties. Theoretical models have come to different conclusions as to the wavelength range impacted by metallicity differences, leading to differing interpretations of the growing sample of UV observations. Recent work has claimed a correlation between the mid-UV flux of SNe Ia measured from Swift grism spectra and the gas-phase metallicities measured for their host galaxies. Here we examine UV photometry for the same objects. We find no significant correlations between the UV-optical colors (or UV/optical count rate ratios) of the SNe Ia and the host-galaxy properties of mass or metallicity. The lack of a significant correlation with host-galaxy metallicity implies that a physical difference other than progenitor metallicity dominates the UV flux differences. Understanding the existing observations requires improved theoretical models and a larger parameter space of physical differences.