# Publications by Joseph Conlon

## Constraints on Massive Axion-Like Particles from X-ray Observations of NGC1275

Monthly Notices of the Royal Astronomical Society (2018)

L Chen, JP Conlon

## The de Sitter swampland conjecture and supersymmetric AdS vacua

International Journal of Modern Physics A World Scientific Publishing (2018)

JP Conlon

It has recently been conjectured that string theory does not admit de Sitter critical points. This note points out that in several cases, including KKLT or racetrack models, this statement is equivalent to the absence of supersymmetric Minkowski or AdS solutions. This equivalence arises from establishing the positivity of the potential in a large-radius limit, requiring a turnover of the potential before reaching an AdS vacuum. For example, this conjecture is incompatible with the simplest 1-modulus KKLT AdS supersymmetric solution.

## Can black hole superradiance be induced by galactic plasmas?

Physics Letters B Elsevier BV (2018)

JP Conlon, CAR Herdeiro

Highly spinning Kerr black holes with masses $M = 1 - 100\ M_{\odot}$ are subject to an efficient superradiant instability in the presence of bosons with masses $\mu \sim 10^{-10} - 10^{-12}\ {\rm eV}$. We observe that this matches the effective plasma-induced photon mass in diffuse galactic or intracluster environments ($\omega_{\rm pl} \sim 10^{-10} - 10^{-12}\ {\rm eV}$). This suggests that bare Kerr black holes within galactic or intracluster environments, possibly even including the ones produced in recently observed gravitational wave events, are unstable to formation of a photon cloud that may contain a significant fraction of the mass of the original black hole. At maximal efficiency, the instability timescale for a massive vector is milliseconds, potentially leading to a transient rate of energy extraction from a black hole in principle as large as $\sim 10^{55} \ {\rm erg \, s}^{-1}$. We discuss possible astrophysical effects this could give rise to, including a speculative connection to Fast Radio Bursts.

## Constraints on axion-like particles from non-observation of spectral modulations for X-ray point sources

JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS (2017) ARTN 005

JP Conlon, F Day, N Jennings, S Krippendorf, M Rummel

## Consistency of Hitomi, XMM-Newton, and Chandra 3.5 keV data from Perseus

PHYSICAL REVIEW D 96 (2017) ARTN 123009

JP Conlon, F Day, N Jennings, S Krippendorf, M Rummel

## Constraints on Axion-like Particles from X-Ray Observations of NGC1275

ASTROPHYSICAL JOURNAL 847 (2017) ARTN 101

M Berg, JP Conlon, F Day, N Jennings, S Krippendorf, AJ Powell, M Rummel

## Galaxy cluster thermal x-ray spectra constrain axionlike particles

PHYSICAL REVIEW D 93 (2016) ARTN 123526

JP Conlon, AJ Powell, MCD Marsh

## Axion decay constants away from the lamppost

JOURNAL OF HIGH ENERGY PHYSICS (2016) ARTN 085

JP Conlon, S Krippendorf

## A 3.55 keV line from DM -> a -> gamma predictions for cool-core and non-cool-core clusters

JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS (2015) ARTN 019

JP Conlon, AJ Powell

## ALP conversion and the soft X-ray excess in the outskirts of the Coma cluster

JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS (2015) ARTN 011

D Kraljic, M Rummel, JP Conlon

## Observational consistency and future predictions for a 3.5 keV ALP to photon line

JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS (2015) ARTN 013

PD Alvarez, JP Conlon, FV Day, MCD Marsh, M Rummel

## 3.55 keV photon lines from axion to photon conversion in the Milky Way and M31

JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS (2014) ARTN 033

JP Conlon, FV Day

## Soft X-ray excess in the Coma cluster from a Cosmic Axion Background

JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS (2014) ARTN 026

S Angus, JP Conlon, MCD Marsh, AJ Powell, LT Witkowski

## A note on the magnitude of the flux superpotential

JOURNAL OF HIGH ENERGY PHYSICS (2014) ARTN 027

M Cicoli, JP Conlon, A Maharana, F Quevedo

## 3.55 keV photon line and its morphology from a 3.55 keV axionlike particle line

PHYSICAL REVIEW D 90 (2014) ARTN 023540

M Cicoli, JP Conlon, MCD Marsh, M Rummel

## Excess Astrophysical Photons from a 0.1–1 keV Cosmic Axion Background

Physics Review Letters 111 (2013) 15130

J Conlon, MCD Marsh

## Dark radiation in LARGE volume models

PHYSICAL REVIEW D 87 (2013) ARTN 043520

M Cicoli, JP Conlon, F Quevedo

## Soft supersymmetry breaking in anisotropic LARGE volume compactifications

JOURNAL OF HIGH ENERGY PHYSICS (2013) ARTN 071

S Angus, JP Conlon

## Superpotential de-sequestering in string models

Journal of High Energy Physics 2013 (2013)

M Berg, JP Conlon, D Marsh, LT Witkowski

Non-perturbative superpotential cross-couplings between visible sector matter and Kähler moduli can lead to significant flavour-changing neutral currents in compactifications of type IIB string theory. Here, we compute corrections to Yukawa couplings in orbifold models with chiral matter localised on D3-branes and non-perturbative effects on distant D7-branes. By evaluating a threshold correction to the D7-brane gauge coupling, we determine conditions under which the non-perturbative corrections to the Yukawa couplings appear. The flavour structure of the induced Yukawa coupling generically fails to be aligned with the tree-level flavour structure. We check our results by also evaluating a correlation function of two D7-brane gauginos and a D3-brane Yukawa coupling. Finally, by calculating a string amplitude between n hidden scalars and visible matter we show how non-vanishing vacuum expectation values of distant D7-brane scalars, if present, may correct visible Yukawa couplings with a flavour structure that differs from the tree-level flavour structure. © 2013 SISSA, Trieste, Italy.

## Cosmological natural selection and the purpose of the universe

Complexity 18 (2013) 48-56

A Gardner, JP Conlon

The cosmological natural selection (CNS) hypothesis holds that the fundamental constants of nature have been fine-tuned by an evolutionary process in which universes produce daughter universes via the formation of black holes. Here, we formulate the CNS hypothesis using standard mathematical tools of evolutionary biology. Specifically, we capture the dynamics of CNS using Price's equation, and we capture the adaptive purpose of the universe using an optimization program. We establish mathematical correspondences between the dynamics and optimization formalisms, confirming that CNS acts according to a formal design objective, with successive generations of universes appearing designed to produce black holes. © 2013 Wiley Periodicals, Inc.