Conveners
DM III
- Yuhsin Tsai (University of Maryland)
The initial data from the Event Horizon Telescope (EHT) on M87$^∗$, the supermassive black hole at the center of the M87 galaxy, provide direct observational information on its mass, spin, and accretion disk properties. A combination of the EHT data and other constraints provide evidence that M87$^∗$ has a mass $\sim6.5\times10^9$ $M_\odot$ and dimensionless spin parameter $|a^∗|\ge0.5$. These...
The massive compact halo objects (MACHOs) such as primordial black holes
or dense mini-halos can gravitational lens the signal of gamma ray bursts (GRB)
and fast radio bursts (FRB). I will discuss that most GRB spectra are
inappropriate for this kind of lensing searches due to their large sizes.
However, FRB lensing, producing a characteristic interference pattern in the
frequency...
Microlensing of stars places significant constraints on sub-planetary mass compact objects, including primordial black holes, as dark matter candidates. However, when the Einstein radius of the lens in the source plane is smaller than the size of the light source, amplification is strongly suppressed, making it difficult to constrain lenses with a mass below ~10^-10 solar masses, i.e....
We consider a minimal extension of the Standard Model with a hidden sector charged under a dark local U(1)′ gauge group, accounting simultaneously for light neutrino masses and the observed Dark Matter relic abundance. The model contains two copies of right-handed neutrinos which give rise to light neutrino-masses via an extended seesaw mechanism. The presence of a stable Dark-Matter...
Dark matter, or a subcomponent of dark matter, could be in the form of dark atoms bound together by a dark U(1). Such objects are predicted in well-motivated models, including Mirror Twin Higgs, and are a good benchmark for general dissipative dark matter models. In this talk I will describe a new way of constraining the abundance of atomic dark matter using white dwarf cooling. If atomic dark...
Non-thermal dark matter produced via freeze-in is a well-motivated scenario and it can explain the null results of direct detection experiment because of its feeble interaction with the standard model (SM) particles. In this work, we have considered a minimal extension of SM by adding an SM gauge singlet and $\mathbb{Z}_2$ odd Dirac fermion $\chi$ which is the dark matter candidate, a pseudo...
Indirect dark matter detection methods are capable of shedding light on numerous dark sector properties. One such method is by searching for annihilation or decay products from regions of high dark matter concentration. A key feature in such analyses is the J-factor which encodes astrophysical properties. The J-factor develops different dependencies based on the nature of the dark sector. We...
