Reconsidering astrophysical constraints on macroscopic dark matter
  Macroscopic dark matter -- "macros"-- refers to a broad class of alternative
candidates to particle dark matter with still unprobed regions of parameter
space. These candidates would transfer energy primarily through elastic
scattering with approximately their geometric cross-section. For sufficiently
large cross-sections, the linear energy deposition could produce observable
signals if a macro were to pass through compact objects such as white dwarfs or
neutron stars in the form of thermonuclear runaway, leading to a type IA
supernova or superburst respectively. We update the constraints from white
dwarfs. These are weaker than previously inferred in important respects because
of more careful treatment of the passage of a macro through the white dwarf and
greater conservatism regarding the size of the region that must be heated to
initiate runaway. On the other hand, we place more stringent constraints on
macros at low cross-section, using new data from the Montreal White Dwarf
Database. New constraints are inferred from the low mass X-ray binary 4U
1820-30, in which more than a decade passed between successive superbursts.
Updated microlensing constraints are also reported.
