Microlensing constraints on clustered primordial black holes
Mihael Petač, Julien Lavalle, Karsten Jedamzik
备注：
9 pages, 1 figure. Comments are welcome! Added two references and slightly updated the text according to the feedback received regarding the first version of the draft
The discovery of black-hole-binary mergers through their gravitational wave (GW) emission has reopened the exciting possibility that dark matter is made, at least partly, of primordial black holes (PBHs). However, this scenario is challenged by many observational probes that set bounds on the relative PBH abundance across a broad range of viable PBH masses. Among these bounds, the ones coming from microlensing surveys lead to the strongest constraints in the mass range from $\sim 10^{-10}$ to a few M$_{\odot}$. The upper part of this range precisely corresponds to the mass window inside which the formation of PBHs should be boosted due to the QCD phase transition in the early Universe, which makes the microlensing probes particularly important. However, it has been argued that taking into account the inevitable clustering of PBH on small scales can significantly relax or entirely remove these bounds. While the impact of PBH clustering on the GW event rate has been studied in detail, its impact on the microlensing event rate has not yet been fully assessed. In this Letter, we address this issue, and show that clusters arising from isocurvature perturbations, that originating from PBHs formed from Gaussian initial curvature perturbations, do not alter the current microlensing constraints, as they are not sufficiently compact.
AMPM I. A Targeted Search for Asteroid Mass Primordial Black Hole Microlenses
Swinburne University of Technology（斯威本科技大学）；ARC Centre of Excellence for Dark Matter Particle Physics（暗物质粒子物理卓越研究中心）；Research School of Astronomy and Astrophysics Australian National University（澳大利亚国立大学天体与天体物理学研究学院）；NSF NOIRLab National Optical-Infrared Astronomy Research Laboratory（美国国家光学红外天文研究实验室）；Cerro Tololo Inter-American Observatory（塞罗托洛洛美洲际观测台）
We show that quasar microlensing magnification statistics induced by a population of point microlenses distributed according to a mass-spectrum can be very well approximated by that of a single-mass, "monochromatic", population. When the spatial resolution (physically defined by the source size) is small as compared with the Einstein radius, the mass of the monochromatic population matches the geometric mean of the mass-spectrum. Otherwise, the best-fit mass can be larger. Taking into account the degeneracy with the geometric mean, the interpretation of quasar microlensing observations under t…
Supernova microlensing as a probe of ultracompact minihalos and primordial cosmology
Institute for Particle Physics Phenomenology, Department of Physics, Durham University（达勒姆大学粒子物理现象学研究所）；Center for Particle Cosmology, Department of Physics and Astronomy, University of Pennsylvania（宾夕法尼亚大学天体物理学与宇宙学中心）；Max Planck Institute for Gravitational Physics (Albert Einstein Institute)（马克斯·普朗克引力物理研究所（阿尔伯特·爱因斯坦研究所））；Instituto de Física Teórica UAM/CSIC（马德里自治大学/西班牙国家研究委员会理论物理研究所）
该研究提出利用超新星微引力透镜搜寻超致密小暗晕等延展暗结构，计算其探测效率并可约束原初功率谱，有望借助Vera C. Rubin天文台的LSST超新星样本成为早期宇宙物理的互补探针。
The accretion of dark matter around the primordial black holes (PBHs) could lead to the formation of surrounding minihalos, whose mass can be several orders of magnitude higher than the central PBH mass. The gravitational microlensing produced by such dressed PBHs could be quite different from that of the bare PBHs, which may significantly affect the constraints on the PBH abundance. In this paper, we study the gravitational microlensing produced by dressed PBHs in detail. We find that all the microlensing effects by dressed PBHs have asymptotic behavior depending on the minihalo size, which c…
Gravitational microlensing is one of the few means of finding primordial black holes (PBHs), if they exist. Recent LIGO detections of 30 Msun black holes have re-invigorated the search for PBHs in the 10-100 Msun mass regime. Unfortunately, individual PBH microlensing events cannot easily be distinguished from stellar lensing events from photometry alone. However, the distribution of microlensing timescales (tE, the Einstein radius crossing time) can be analyzed in a statistical sense using models of the Milky Way with and without PBHs. While previous works have presented both theoretical mode…
Stellar microlensing observations tightly constrain compact object dark matter in the mass range $(10^{-11} - 10^{3}) M_{\odot}$. Primordial Black Holes (PBHs) form clusters, and it has been argued that these microlensing constraints are consequently weakened or evaded. For the most commonly studied PBH formation mechanism, the collapse of large gaussian curvature perturbations generated by inflation, the clusters are sufficiently extended that the PBHs within them act as individual lenses. We find that if the typical mass of the clusters is sufficiently large, $ \gtrsim 10^{6} M_{\odot}$, the…
Microlensing Signatures of Dyson Sphere-like Structures around Primordial Black Holes as Technosignatures of Extraterrestrial Advanced Civilizations
Sharif University of Technology（谢里夫理工大学）；Research Center for High Energy Physics, Department of Physics, Sharif University of Technology（谢里夫理工大学物理系高能物理研究中心）
The National Research Centre Kurchatov Institute（库尔恰托夫国家研究中心）；Space Research Institute, Russian Academy of Sciences（俄罗斯科学院空间研究所）；Lebedev Physical Institute, Russian Academy of Sciences（俄罗斯科学院列别捷夫物理研究所）；National Research Nuclear University (MEPhI)（国立核研究大学（莫斯科工程物理学院））；Novosibirsk State University（新西伯利亚国立大学）；Sternberg Astronomical Institute, Moscow State University（莫斯科大学斯登伯格天文研究所）
Primordial black holes (PBHs) have long been suggested as a viable candidate for the elusive dark matter (DM). The abundance of such PBHs has been constrained using a number of astrophysical observations, except for a hitherto unexplored mass window of $M_{\rm PBH}=[10^{-14},10^{-9}]M_\odot$. Here we carry out a dense-cadence (2~min sampling rate), 7 hour-long observation of the Andromeda galaxy (M31) with the Subaru Hyper Suprime-Cam to search for microlensing of stars in M31 by PBHs lying in the halo regions of the Milky Way (MW) and M31. Given our simultaneous monitoring of tens of millions…
Combining constraints from microlensing and Lyman-$α$ forest, we provide a simple argument to show that large spatial clustering of stellar-mass primordial black holes at the time of formation, such as the one induced by the presence of large non-Gaussianities, is ruled out. Therefore, it is not possible to evade existing constraints preventing stellar-mass primordial black holes to be a dominant constituent of the dark matter by boosting their initial clustering.
Recent observations of gravitational waves motivate investigations for the existence of Primordial Black Holes (PBHs). We propose the observation of gravitational microlensing of distant quasars for the range of infrared to the submillimeter wavelengths by sub-lunar PBHs as lenses. The advantage of observations in the longer wavelengths, comparable to the Schwarzschild radius of the lens (i.e. $R_{\rm sch}\simeq λ$) is the detection of the wave optics features of the gravitational microlensing. The observation of diffraction pattern in the microlensing light curve of a quasar can break the deg…
Primordial black holes (PBHs), hypothesized to be the result of density fluctuations during the early universe, are candidates for dark matter. When microlensing background stars, they cause a transient apparent enhancement of the flux. Measuring these signals with optical telescopes is a powerful method to constrain the PBH abundance in the range of $10^{-10}\,M_{\odot}$ to $10^{1}\,M_{\odot}$. Especially for galactic stars, the finiteness of the sources needs to be taken into account. For low PBH masses (in this work $\lesssim 10^{-8}\,M_{\odot}$) the average duration of the detectable event…
The idea of dark matter in the form of primordial black holes has seen a recent revival triggered by the LIGO detection of gravitational waves from binary black hole mergers. In this context, it has been argued that a large initial clustering of primordial black holes can help alleviate the strong constraints on this scenario. In this work, we show that on the contrary, with large initial clustering the problem is exacerbated and constraints on primordial black hole dark matter become overwhelmingly strong.
The aim of this paper is to provide a plausible explanation for the large amplitude microlensing events observed in the cluster lensed quasar system SDSS J1004+4112. The microlensed quasar images appear to lie well clear of the stellar population of the cluster, raising the possibility that the cluster dark matter is composed of compact bodies which are responsible for the observed microlensing. In the first part of the paper we establish the exact structure of the difference light curves attributed to microlensing from photometric monitoring programmes in the literature. We then show from mea…
The Mass Function of Primordial Rogue Planet MACHOs in quasar nanolensing
最近Sumi等人（2010，2011）在宇宙学上显著数量的自由漫游行星质量MACHO的检测回顾了它们在类星体微透镜化研究中的原始检测（Schild 1996，Colley and Schild 2003）。我们考虑了这样的人口的微透镜签名，并发现纳米透镜（微透镜）将很好地表征由Refsdal和Stabel（1991）先前发表的统计微透镜理论。所观察到的第一透镜微透镜振幅与理论预测的比较给出了密切的一致性和用于确定描述人口的质量函数的斜率的方法。我们对幂律指数的临时估计是$2.98^{+1.0}_{-0.5}.$，其中Salpeter斜率为2.35。
Microlensing of stars, e.g. in the Galactic bulge and Andromeda galaxy (M31), is among the most robust, powerful method to constrain primordial black holes (PBHs) that are a viable candidate of dark matter. If PBHs are in the mass range $M_{\rm PBH} \lower.5ex\hbox{$\; \buildrel < \over \sim \;$} 10^{-10}M_\odot$, its Schwarzschild radius ($r_{\rm Sch}$) becomes comparable with or shorter than optical wavelength ($λ)$ used in a microlensing search, and in this regime the wave optics effect on microlensing needs to be taken into account. For a lensing PBH with mass satisfying $r_{\rm Sch}\sim λ…
AMPM II. A Lunar-Mass Primordial Black Hole Microlensing Candidate in the Milky Way Halo
Swinburne University of Technology（斯威本科技大学）；ARC Centre of Excellence for Dark Matter Particle Physics（暗物质粒子物理卓越研究中心）；Australian National University（澳大利亚国立大学）；NSF NOIRLab National Optical-Infrared Astronomy Research Laboratory（美国国家光学红外天文研究实验室）；Cerro Tololo Inter-American Observatory（塞罗托洛美洲际天文台）
Merger rate of initially clustered primordial black holes for the two-body channel
Theory Center, Institute of Particle and Nuclear Studies (IPNS), High Energy Accelerator Research Organization (KEK)（高能加速器研究机构粒子与核研究研究所理论中心）；ICRR, University of Tokyo（东京大学宇宙射线研究所）；Kavli IPMU (WPI), UTIAS, University of Tokyo（东京大学 Kavli 宇宙起源与物质研究所（世界顶尖学术研究中心）、宇宙前沿机构）；RIKEN Center for Interdisciplinary Theoretical and Mathematical Sciences (iTHEMS), RIKEN（理化学研究所交叉理论与数学科学中心）；Department of Physics, Tohoku University（东北大学物理学系）
We constrain the abundance of primordial black holes (PBH) using 2622 microlensing events obtained from 5-years observations of stars in the Galactic bulge by the Optical Gravitational Lensing Experiment (OGLE). The majority of microlensing events display a single or at least continuous population that has a peak around the light curve timescale $t_{\rm E}\simeq 20~{\rm days}$ and a wide distribution over the range $t_{\rm E}\simeq [1, 300]~{\rm days}$, while the data also indicates a second population of 6 ultrashort-timescale events in $t_{\rm E}\simeq [0.1,0.3]~{\rm days}$, which are advoca…
The aim of this paper is to investigate the claim that stars in the lensing galaxy of a gravitationally lensed quasar system can always account for the observed microlensing of the individual quasar images. A small sample of gravitationally lensed quasar systems was chosen where the quasar images appear to lie on the fringe of the stellar distribution of the lensing galaxy. As with most quasar systems, all the individual quasar images were observed to be microlensed. The surface brightness of the lensing galaxy at the positions of the quasar images was measured from HST frames, and converted t…
Fast Lensing And Sub-minute High-accuracy photometry (FLASH) with JWST: Pipeline and Primordial Black Hole Microlensing Constraints from M31
University of Hawai‘i at Mānoa（夏威夷大学马诺阿分校）；E.O. Lawrence Berkeley National Laboratory（劳伦斯伯克利国家实验室）；Institute for Astronomy, University of Hawai‘i at Mānoa（夏威夷大学马诺阿分校天文研究所）
Microlensing constraints on Primordial Black Hole abundance with Subaru Hyper Suprime-Cam observations of Andromeda
University of Pennsylvania（宾夕法尼亚大学）；The University of Tokyo（东京大学）；Kavli Institute for the Physics and Mathematics of the Universe (WPI)（宇宙物理与数学 Kavli 研究所 (WPI)）；Institutes for Advanced Study (UTIAS), The University of Tokyo（东京大学高等研究院 (UTIAS)）；Center for Data-Driven Discovery (CD3), Kavli IPMU (WPI), UTIAS, The University of Tokyo（东京大学数据驱动发现中心 (CD3)，Kavli IPMU (WPI)，UTIAS）；National Astronomical Observatory of Japan（日本国立天文台）；The Graduate University for Advanced Studies (SOKENDAI)（综合研究大学院大学 (SOKENDAI)）；Konan University（神户学院大学）
In this paper we show that to explain the observed distribution of amplitudes in a large sample of quasar lightcurves, a significant contribution from microlensing is required. This implies the existence of a cosmologically distributed population of stellar mass compact bodies making up a large fraction of the dark matter. Our analysis is based on the lightcurves of a sample of over 1000 quasars, photometrically monitored over a period of 26 years. The intrinsic variations in quasar luminosity are derived from luminous quasars where the quasar accretion disc is too large to be microlensed by s…
A Unified Origin of Primordial Black Hole Dark Matter and Nanohertz Gravitational Waves
Leibniz University Hannover（汉诺威莱布尼茨大学）；Max-Planck-Institut für Gravitationsphysik, Albert-Einstein-Institut（马克斯·普朗克引力物理学研究所，阿尔伯特·爱因斯坦研究所）；Institute of Theoretical Physics, Chinese Academy of Sciences（中国科学院理论物理研究所）；Center for High Energy Physics, Peking University（北京大学高能物理中心）；Kavli Institute for the Physics and Mathematics of the Universe (WPI), The University of Tokyo（东京大学宇宙物质与宇宙学 Kavli 前沿研究所（WPI））；School of Physical Sciences, University of Chinese Academy of Sciences（中国科学院大学物理科学学院）；Department of Physics, Kyoto University（京都大学物理系）
Evidence for Intermediate-Mass Black Holes From Microlensing Signatures in CHIME/FRB catalog 2
School of Physics and Optoelectronic Engineering, Yangtze University（长江大学物理与光电工程学院）；School of Physics and Astronomy, Beijing Normal University（北京师范大学物理学院）；Institute for Frontiers in Astronomy and Astrophysics, Beijing Normal University（北京师范大学天文与前沿科学研究院）；School of Physics and Technology, Wuhan University（武汉大学物理科学与技术学院）
Two gravitational wave events, i.e. GW200105 and GW200115, were observed by the Advanced LIGO and Virgo detectors recently. In this work, we show that they can be explained by a scenario of primordial black hole binaries that are formed in the early Universe. The merger rate predicted by such a scenario could be consistent with the one estimated from LIGO and Virgo, even if primordial black holes constitute a fraction of cold dark matter. The required abundance of primordial black holes is compatible with the existing upper limits from microlensing, caustic crossing and cosmic microwave backgr…
We study the prospects of future gravitational wave (GW) detectors in probing primordial black hole (PBH) binaries. We show that across a broad mass range from $10^{-5}M_\odot$ to $10^7M_\odot$, future GW interferometers provide a potential probe of the PBH abundance that is more sensitive than any currently existing experiment. In particular, we find that galactic PBH binaries with masses as low as $10^{-5}M_\odot$ may be probed with ET, AEDGE and LISA by searching for nearly monochromatic continuous GW signals. Such searches could independently test the PBH interpretation of the ultrashort m…
We argue that primordial dark matter halos could be generated during radiation domination by long range attractive forces stronger than gravity. In this paper we derive the conditions under which these structures could dominate the dark matter content of the Universe while passing microlensing constraints and cosmic microwave background energy injection bounds. The dark matter particles would be clumped in objects in the solar mass range with typical sizes of the order of the solar system. Consequences for direct dark matter searches are important.
The next generation of gravitational-wave experiments, such as Einstein Telescope, Cosmic Explorer and LISA, will test the primordial black hole scenario. We provide a forecast for the minimum testable value of the abundance of primordial black holes as a function of their masses for both the unclustered and clustered spatial distributions at formation. In particular, we show that these instruments may test abundances, relative to the dark matter, as low as $10^{-10}$.
