Publications (75)
Connecting Faint End Slopes of the Lyman- emitter and Lyman-break Galaxy Luminosity Functions
Max Gronke, Mark Dijkstra, Michele Trenti +1
We predict Lyman- (Ly) luminosity functions (LFs) of Ly-selected galaxies (Ly emitters, or LAEs) at using the phenomenological model of Dijkstra & Wyithe (2…
Hubble Space Telescope Wide Field Camera 3 Observations of Escaping Lyman Continuum Radiation from Galaxies and Weak AGN at Redshifts 2.3-4.1
Brent M. Smith, Rogier A. Windhorst, Rolf A. Jansen +9
We present observations of escaping Lyman Continuum (LyC) radiation from 34 massive star-forming galaxies and 12 weak AGN with reliably measured spectroscopic redshifts at $\sim…
The LyAlpha Line Profiles of Ultraluminous Infrared Galaxies: Fast Winds and Lyman Continuum Leakage
Crystal L. Martin, Mark Dijkstra, Alaina Henry +3
We present new Hubble Space Telescope Cosmic Origins Spectrograph far-ultraviolet (far-UV) spectroscopy and Keck Echellete optical spectroscopy of 11 ultraluminous infrared galaxie…
Fluctuations in the High-Redshift Lyman-Werner Background: Close Halo Pairs as the Origin of Supermassive Black Holes
Mark Dijkstra, Zoltan Haiman, Andrei Mesinger +1
The earliest generation of stars and black holes must have established an early 'Lyman-Werner' background (LWB) at high redshift, prior to the epoch of reionization. Because of the…
The Universe is Reionizing at z~7: Bayesian Inference of the IGM Neutral Fraction Using Ly Emission from Galaxies
Charlotte A. Mason, Tommaso Treu, Mark Dijkstra +5
We present a new flexible Bayesian framework for directly inferring the fraction of neutral hydrogen in the intergalactic medium (IGM) during the Epoch of Reionization (EoR, z~6-10…
Small-scale Intensity Mapping: Extended Halos as a Probe of the Ionizing Escape Fraction and Faint Galaxy Populations during Reionization
LluÃs Mas-Ribas, Joseph F. Hennawi, Mark Dijkstra +3
We present a new method to quantify the value of the escape fraction of ionizing photons, and the existence of ultra-faint galaxies clustered around brighter objects during the epo…
Constraining Reionization with Lyman Alpha Emitting Galaxies
Mark Dijkstra
Neutral diffuse intergalactic gas that existed during the Epoch of Reionization (EoR) suppresses Lyman Alpha (Lya) flux emitted by background galaxies. In this chapter I summarise…
Ly profile, dust, and prediction of Ly escape fraction in Green Pea Galaxies
Huan Yang, Sangeeta Malhotra, Max Gronke +7
We studied Lyman- (Ly) escape in a statistical sample of 43 Green Peas with HST/COS Ly spectra. Green Peas are nearby star-forming galaxies with strong [OIII]5007 e…
Small-scale Intensity Mapping: Extended Ly, H and Continuum emission as a Probe of Halo Star Formation in High-redshift Galaxies
LluÃs Mas-Ribas, Mark Dijkstra, Joseph F. Hennawi +3
Lyman alpha halos are observed ubiquitously around star-forming galaxies at high redshift, but their origin is still a matter of debate. We demonstrate that the emission from faint…
UV Radiative Feedback During the Advanced Stages of Reionization
Andrei Mesinger, Mark Dijkstra
The ionizing ultraviolet background (UVB) during reionization can suppress the gas content of low-mass galaxies, even those capable of efficient atomic cooling, and thus lead to an…
A Limit from the X-ray Background on the Contribution of Quasars to Reionization
Mark Dijkstra, Zoltan Haiman, Abraham Loeb
A population of black holes (BHs) at high redshifts (z>6) that contributes significantly to the ionization of the intergalactic medium (IGM) would be accompanied by the copious pro…
Ly Spectra from Multiphase Outflows, and their Connection to Shell Models
Max Gronke, Mark Dijkstra
We perform Lyman- (Ly) Monte-Carlo radiative transfer calculations on a suite of models of multiphase, outflowing media, which are characterized by parameters.…
Saas-Fee Lecture Notes: Physics of Lyman Alpha Radiative Transfer
Mark Dijkstra
Lecture notes for 8 lectures on the `Physics of Lyman alpha Radiative Transfer', given at the 46th Saas-Fee winter school held in Les Diablerets, Switzerland on March 13-19 2016. T…
Evolution in the Escape Fraction of Ionizing Photons and the Decline in Strong Lya Emission from z>6 Galaxies
Mark Dijkstra, Stuart Wyithe, Zoltan Haiman +2
The rapid decline in the number of strong Lyman Alpha (Lya) emitting galaxies at z > 6 provides evidence for neutral hydrogen in the IGM, but is difficult to explain with plausible…
Unlocking the Full Potential of Extragalactic Ly through Its Polarization Properties
Marius B. Eide, Max Gronke, Mark Dijkstra +1
Lyman- (Ly) is a powerful astrophysical probe. Not only is it ubiquitous at high redshifts, it is also a resonant line, making Ly photons scatter. This scattering proce…
Resonant line transfer in a fog: Using Lyman-alpha to probe tiny structures in atomic gas
Max Gronke, Mark Dijkstra, Michael McCourt +1
Motivated by observational and theoretical work which both suggest very small scale (pc) structure in the circum-galactic medium of galaxies and in other environments…
Seeing Through the Trough: Outflows and the Detectability of Lyman Alpha Emission from the First Galaxies
Mark Dijkstra, Stuart Wyithe
The next generation of telescopes aim to directly observe the first generation of galaxies that initiated the reionization process in our Universe. The Lyman Alpha (Lya) emission l…
Evidence for Infalling Gas in a Lyman- Blob
Yiping Ao, Zheng Zheng, Christian Henkel +11
Lyman- blobs (LABs) are spatially extended nebulae of emission in the Ly line of hydrogen, seen at high redshifts, and most commonly found in the dense environment…
Lyman-Alpha Emitting Galaxies as a Probe of Reionization: Large-Scale Bubble Morphology and Small-Scale Absorbers
Koki Kakiichi, Mark Dijkstra, Benedetta Ciardi +1
The visibility of LyA emitting galaxies during the Epoch of Reionization is controlled by both diffuse HI patches in large-scale bubble morphology and small-scale absorbers. To inv…
ALMA [CII] detection of a redshift 7 lensed galaxy behind RXJ1347.1-1145
MaruÅ¡a BradaÄ, Diego Garcia-Appadoo, Kuang-Han Huang +13
We present the results of ALMA spectroscopic follow-up of a Lyman- emitting galaxy behind the cluster RXJ1347-1145. We report the detection of [CII]158m line full…
Beyond Lyman-alpha: Constraints and Consistency Tests from the Lyman-beta Forest
Mark Dijkstra, Adam Lidz, Lam Hui
Absorption between the rest-frame wavelengths of 973 and 1026 Angstroms in quasar spectra arises from two sources (apart from occasional metals): one is due to Lyman-alpha (Lya) ab…
On the observability of individual Population III stars and their stellar-mass black hole accretion disks through cluster caustic transits
Rogier A. Windhorst, F. X. Timmes, J. Stuart B. Wyithe +8
We summarize panchromatic Extragalactic Background Light data to place upper limits on the integrated near-infrared surface brightness (SB) that may come from Population III stars…
Effect of Intergalactic Medium on the Observability of Lyman Alpha Emitters during Cosmic Reionization
Akila Jeeson-Daniel, Benedetta Ciardi, Umberto Maio +3
We perform a systematic study of how the inhomogeneities in the Inter-Galactic Medium (IGM) affect the observability of Lyman Alpha Emitters (LAEs) around the Epoch of Reionization…
On the contribution of fluorescence to Ly halos (LAHs) around star forming galaxies
LluÃs Mas-Ribas, Mark Dijkstra
We quantify the contribution of Ly fluorescence to observed spatially extended Ly halos around Ly emitters (LAE) at redshift . The key physical quantities…
An Empirical Study of the Relationship between Lyα and UV selected Galaxies: Do Theorists and Observers `Select' the Same Objects?
Mark Dijkstra, Stuart Wyithe
Lyman Alpha Emitters (LAEs) are galaxies that have been selected on the basis of a strong Lyα emission line in their spectra. Observational campaigns have dramatically increased t…
On Detecting the X-ray Silhouette of a Damped Lyman alpha System
Mark Dijkstra, Zoltan Haiman, Caleb Scharf
We explore the possibility of resolving an image of a damped Lyman alpha (DLA) system in absorption against an extended, diffuse background X-ray source. Typical columns of neutral…
The Impact of Scatter in the Galaxy UV Luminosity to Halo Mass Relation on Ly Visibility During the Epoch of Reionization
Lily R. Whitler, Charlotte A. Mason, Keven Ren +5
The reionization of hydrogen is closely linked to the first structures in the universe, so understanding the timeline of reionization promises to shed light on the nature of these…
Lyman Alpha Constraints on Very Low Luminosity AGN
Mark Dijkstra, Stuart Wyithe
Recent surveys have detected Lya emission from z=4.5-6.5 at luminosities as low as 10^41 erg/s. There is good evidence that low numbers of AGN are among observed faint Lya emitters…
Requirements for Cosmological 21-cm Masers
Mark Dijkstra, Abraham Loeb
We perform Monte-Carlo calculations of the radiative transfer of Lyman Alpha (hereafter Lya) photons emitted by a source embedded in a neutral collapsing gas cloud. This represents…
Empirical Constraints on the Star Formation & Redshift Dependence of the Lyman Alpha `Effective' Escape Fraction
Mark Dijkstra, Akila Jeeson-Daniel
We derive empirical constraints on the volume averaged `effective' escape fraction of Lyman Alpha (Lya) photons from star forming galaxies as a function of redshift, by comparing s…
The Polarization of Scattered Lyman Alpha Radiation Around High-Redshift Galaxies
Mark Dijkstra, Abraham Loeb
The high-redshift Universe contains luminous Lyman Alpha (hereafter Lya) emitting sources such as galaxies and quasars. The emitted Lya radiation is often scattered by surrounding…
Prospects for Detecting the First Black Holes with the Next Generation of Telescopes
Mark Dijkstra
This chapter describes the prospects for detecting the first black holes in our Universe, with a specific focus on instruments/telescopes that will come online within the next deca…
From Mirrors to Windows: Lyman-Alpha Radiative Transfer in a Very Clumpy Medium
Max Gronke, Mark Dijkstra, Michael McCourt +1
Lyman-Alpha (Ly) is the strongest emission line in the Universe and is frequently used to detect and study the most distant galaxies. Because Lya is a resonant line, photons ty…
Blue Wings and Bumps via Fermi-like Acceleration of Lyman-alpha photons across Shocks
Andrew S. Chung, Mark Dijkstra, Benedetta Ciardi +1
We explore the impact of Fermi-like acceleration of Lyman-alpha (Lyα) photons across shock fronts on the observed Lyα spectral line shape. We first confirm the result of Neufeld…
The Detectability of Lyman Alpha Emission from Galaxies during the Epoch of Reionization
Mark Dijkstra, Andrei Mesinger, Stuart Wyithe
We study the visibility of the Lyman Alpha (Lya) emission line during the Epoch of Reionization (EoR). Combining galactic outflow models with large-scale semi-numeric simulations o…
Lyman Alpha Driven Outflows Around Star Forming Galaxies
Mark Dijkstra, Abraham Loeb
We present accurate Monte-Carlo calculations of Lyman Alpha (hereafter Lya) radiation pressure in a range of models which represent galaxies during various epochs of our Universe.…
The impact of gas bulk rotation on the lyman-alpha line
Juan N. Garavito-Camargo, Jaime E. Forero-Romero, Mark Dijkstra
We present results of radiative transfer calculations to measure the impact of gas bulk rotation on the morphology of the Lyman emission line in distant galaxies. We model a g…
Feedback-regulated Super Massive Black Hole Seed Formation
Mark Dijkstra, Andrea Ferrara, Andrei Mesinger
The nature of the seeds of high-redshift supermassive black holes (SMBHs) is a key question in cosmology. Direct collapse black holes (DCBH) that form in pristine, atomic-line cool…
Continuum Emission by Cooling Clouds
Mark Dijkstra
The collapse of baryons into the center of a host dark matter halo is accompanied by radiation that may be detectable as compact (< 10 kpc) UV-continuum and Lyman Alpha (hereafter…
Star Formation Indicators and Line Equivalent Width in Lyman Alpha Galaxies
Mark Dijkstra, Eduard Westra
The equivalent width (EW) of the Lyman Alpha (Lya) line is directly related to the ratio of star formation rates determined from Lya flux and UV flux density [SFR(Lya)/SFR(UV)]. We…
Directional Lya equivalent boosting I. Spherically symmetric distributions of clumps
Max Gronke, Mark Dijkstra
We quantify the directional dependence of the escape fraction of Lyman- (Ly) and non-ionising UV-continuum photons from a multiphase medium, and investigate whether there e…
Lyman Alpha Radiation From Collapsing Protogalaxies II: Observational Evidence for Gas Infall
Mark Dijkstra, Zoltan Haiman, Marco Spaans
We model the spectra and surface brightness distributions for the Lyman alpha (Lya) radiation expected from protogalaxies that are caught in the early stages of their assembly. We…
Lyman Alpha Emitting Galaxies as a Probe of Reionization
Mark Dijkstra
The Epoch of Reionization (EoR) represents a milestone in the evolution of our Universe. Star-forming galaxies that existed during the EoR likely emitted a significant fraction (~5…
Spectro-polarimetry confirms central powering of a Ly nebula at z=3.09
Melanie Beck, Claudia Scarlata, Matthew Hayes +2
We present a follow-up study to the imaging polarimetry performed by Hayes et. al. 2011 on LAB1 in the SSA22 protocluster region. Arguably the most well-known Lyman- "blob", th…
The LyA-LyC Connection: Evidence for an Enhanced Contribution of UV-faint Galaxies to Cosmic Reionization
Mark Dijkstra, Max Gronke, Aparna Venkatesan
The escape of ionizing Lyman Continuum (LyC) photons requires the existence of low-N_HI sightlines, which also promote escape of Lyman-Alpha (Lya). We use a suite of 2500 Lya Monte…
The Impact of The IGM on High-Redshift Lyman Alpha Emission Lines
Mark Dijkstra, Adam Lidz, Stuart Wyithe
We calculate the impact of the intergalactic medium (IGM) on the observed Lyman alpha lines (hereafter Lya) emitted by galaxies in an ionised IGM at z>4. Our model accounts for gas…
Non-Gravitational Contributions to the Clustering of Ly-alpha Selected Galaxies: Implications for Cosmological Surveys
Stuart Wyithe, Mark Dijkstra
We show that the dependence of Ly-alpha absorption on environment leads to significant non-gravitational features in the redshift space power-spectrum of Ly-alpha selected galaxies…
Modelling the gas kinematics of an atypical Lyman-alpha emitting compact dwarf galaxy
Jaime E. Forero-Romero, Max Gronke, Maria Camila Remolina-Gutiérrez +2
Star-forming Compact Dwarf Galaxies (CDGs) resemble the expected pristine conditions of the first galaxies in the Universe and are the best systems to test models on primordial gal…
Photoionization Feedback in Low--Mass Galaxies at High Redshift
Mark Dijkstra, Zoltan Haiman, Martin J. Rees +1
The cosmic ultraviolet (UV) ionizing background impacts the formation of dwarf galaxies in the low-redshift universe (z=3) by suppressing gas infall into galactic halos with circul…
A new model framework for circumgalactic Ly radiative transfer constrained by galaxy-Ly forest clustering
Koki Kakiichi, Mark Dijkstra
We present a new perturbative approach to "constrained Ly radiative transfer'" (RT) through the circum- and inter-galactic medium (CGM and IGM). We constrain the HI content and…
Boosting Lya and HeII 1640A Line Fluxes from Pop III Galaxies: Stochastic IMF Sampling and Departures from Case-B
LluÃs Mas-Ribas, Mark Dijkstra, Jaime E. Forero-Romero
We revisit calculations of nebular hydrogen Lya and HeII 1640A line strengths for population III galaxies, undergoing continuous and bursts of star formation. We focus on initial m…
Beamed Lyman Alpha Emission through Outflow-Driven Cavities
Christoph Behrens, Mark Dijkstra, Jens Niemeyer
We investigate the radiative transfer of Lyman alpha photons through simplified anisotropic gas distributions, which represent physically motivated extensions of the popular 'shell…
Constraints on the Redshift Evolution of the L_X-SFR Relation from the Cosmic X-Ray Backgrounds
Mark Dijkstra, M. Gilfanov, Abraham Loeb +1
Observations of local star forming galaxies have revealed a correlation between the rate at which galaxies form stars and their X-Ray luminosity. We combine this correlation with t…
Green Pea Galaxies Reveal Secrets of Ly Escape
Huan Yang, Sangeeta Malhotra, Max Gronke +5
We analyze archival Ly spectra of 12 "Green Pea" galaxies observed with the Hubble Space Telescope, model their Ly profiles with radiative transfer models, and explore the…
Luminosity Functions of Lyman Alpha Emitting Galaxies and Cosmic Reionization of Hydrogen
Mark Dijkstra, Stuart Wyithe, Zoltan Haiman
Recent observations imply that the observed number counts of Lya Emitters (LAEs) evolved significantly between z=5.7 and z=6.5. It has been suggested that this was due to a rapid e…
On the Detectability of the Hydrogen 3-cm Fine Structure Line from the EoR
Mark Dijkstra, Adam Lidz, Jonathan R. Pritchard +4
A soft ultraviolet radiation field, 10.2 eV < E <13.6 eV, that permeates neutral intergalactic gas during the Epoch of Reionization (EoR) excites the 2p (directly) and 2s (indirect…
Enhanced direct collapse due to Lyman alpha feedback
Jarrett L. Johnson, Mark Dijkstra
We assess the impact of trapped Lyman alpha cooling radiation on the formation of direct collapse black holes (DCBHs). We apply a one-zone chemical and thermal evolution model, acc…
3-cm Fine Structure Masers: A Unique Signature of Supermassive Black Hole Formation via Direct Collapse in the Early Universe
Mark Dijkstra, Shiv Sethi, Abraham Loeb
The direct collapse black hole (DCBH) scenario describes the isothermal collapse of a pristine gas cloud directly into a massive, M_BH=10^4-10^6 M_sun black hole. In this paper we…
Can the intergalactic medium cause a rapid drop in Lyman alpha emission at z>6?
Andrei Mesinger, Aycin Aykutalp, Eros Vanzella +3
The large cross-section of the Lyman alpha (Lya) line makes it a sensitive probe of the ionization state of the intergalactic medium (IGM). Here we present the most complete study…
Clustering of Ly-alpha emitters around luminous quasars at z = 2-3: an alternative probe of reionization on galaxy formation
Loren R. Bruns, J. Stuart B. Wyithe, Joss Bland-Hawthorn +1
Narrowband observations have detected no Ly-alpha emission within a 70 pMpc^3 volume centered on the z = 2.168 quasar PKS 0424-131. This is in contrast to surveys of Ly-alpha emitt…
Detection of Lyman-Alpha Emission From a Triple Imaged z=6.85 Galaxy Behind MACS J2129.4-0741
Kuang-Han Huang, Brian C. Lemaux, Kasper B. Schmidt +13
We report the detection of Ly emission at à in the Keck/DEIMOS and \HST WFC3 G102 grism data from a triply-imaged galaxy at behind galaxy cluster MA…
A bright lensed galaxy at with strong Ly emission
Ian D. McGreer, Benjamin Clément, Ramesh Mainali +10
We present a detailed study of a unusually bright, lensed galaxy at discovered within the CFHTLS imaging survey. With an observed flux of , J141446.82+54…
Effects of Star Formation Stochasticity on the Ly-alpha & Lyman Continuum Emission from Dwarf Galaxies during Reionization
Jaime E. Forero-Romero, Mark Dijkstra
Observations of distant galaxies play a key role in improving our understanding of the Epoch of Reionization (EoR). The observed Ly-alpha emission line strength - quantified by its…
A systematic study of Lyman-Alpha transfer through outflowing shells: Model parameter estimation
Max Gronke, Philip Bull, Mark Dijkstra
Outflows promote the escape of Lyman- (Ly) photons from dusty interstellar media. The process of radiative transfer through interstellar outflows is often modelled by a sph…
The circumgalactic medium in Lyman-alpha: a new constraint on galactic outflow models
Andrew S. Chung, Mark Dijkstra, Benedetta Ciardi +2
Galactic outflows are critical to our understanding of galaxy formation and evolution. However the details of the underlying feedback process remain unclear. We compare Ly obse…
Beacons into the Cosmic Dark Ages: Boosted transmission of Ly from UV bright galaxies at
Charlotte A. Mason, Tommaso Treu, Stephane de Barros +6
Recent detections of Lyman alpha (Ly) emission from galaxies were somewhat unexpected given a dearth of previous non-detections in this era when the intergalactic mediu…
Lyman Alpha Signatures from Direct Collapse Black Holes
Mark Dijkstra, Max Gronke, David Sobral
`Direct collapse black holes' (DCBHs) provide possible seeds for supermassive black holes that exist at redshifts as high as z~7. We study Lyman Alpha (Lya) radiative transfer thro…
Upper Limit on Dimming of Cosmological Sources by Intergalactic Grey Dust from the Soft X-ray Background
Mark Dijkstra, Abraham Loeb
Active Galactic Nuclei (AGN) produce a dominant fraction (~80%) of the Soft X-ray background (SXB) at photon energies 0.5<E<2 keV. If dust pervaded throughout the intergalactic med…
The Growth of the Earliest Supermassive Black Holes and Their Contribution to Reionization
Zoltan Haiman, Mark Dijkstra, Andrei Mesinger
We discuss currently available observational constraints on the reionization history of the intergalactic medium (IGM), and the extent to which accreting black holes (BHs) can help…
Line Transfer through Clumpy, Large-Scale Outflows: Lyman Alpha Absorption and Halos around Starforming Galaxies
Mark Dijkstra, Roban Hultman Kramer
We present constrained radiative transfer calculations of Lyman Alpha (Lya) photons propagating through clumpy, dusty, large scale outflows, and explore whether we can quantitative…
Very Massive Stars in High-Redshift Galaxies
Mark Dijkstra, Stuart Wyithe
A significant fraction of Lyman Alpha (Lya) emitting galaxies (LAEs) at z> 5.7 have rest-frame equivalent widths (EW) greater than ~100 Angstrom. However only a small fraction of t…
Lyman Alpha Radiation From Collapsing Protogalaxies I: Characteristics of the Emergent Spectrum
Mark Dijkstra, Zoltan Haiman, Marco Spaans
We present Monte Carlo calculations of Lyman alpha (Lya) radiative transfer through collapsing gas clouds, representing proto-galaxies that are caught in the process of their assem…
Observational Signatures of Lyman Alpha Emission from Early Galaxy Formation
Mark Dijkstra
The next generation of telescopes aim to directly observe the first generation of galaxies that initiated the reionization process in our Universe. The Lyman Alpha (Lya) emission l…
Lyman Alpha Blobs as an Observational Signature of Cold Accretion Streams into Galaxies
Mark Dijkstra, Abraham Loeb
Recent hydrodynamic simulations of galaxy formation reveal streams of cold (T ~ 1e4 K) gas flowing into the centers of dark matter halos as massive as 1e12-1e13.5 M_sun at redshift…
Acceleration of Galactic Supershells by Lyman Alpha Radiation
Mark Dijkstra, Abraham Loeb
Scattering of Lyman Alpha (hereafter Lya) photons by neutral hydrogen gas in a single outflowing 'supershell' around star forming regions often explains the shape and offset of the…