CCAPP AstroParticle Lunch

Here, members of CCAPP, Physics, and Astronomy get together to discuss papers and recent developments in high-energy astrophysics and astroparticle physics, in an informal setting over lunch. Please check the page for details regarding the next meeting.

Organizers:

Lucas Beaufore -- beaufore.2@osu.eduObada Nairat -- nairat.2@osu.eduPaarmita Pandey -- pandey.176@osu.edu

Fridays from 11:30 am - 12:30 pm (EST)

Price Place (PRB) & VIA ZOOM

COMING UP:

11:30, Friday, February 7

Use this link to access the meeting: ZOOM

Guest: Sarah Mancina (University of Padova)

Title: Time-Integrated Southern-Sky Neutrino Source Searches with 10 Years of IceCube Starting-Track Events at Energies Down to 1 TeV

Abstract: In the IceCube Neutrino Observatory, a signal of astrophysical neutrinos is obscured by backgrounds from atmospheric neutrinos and muons produced in cosmic-ray interactions. IceCube event selections used to isolate the astrophysical neutrino signal often focus on the morphology of the light patterns recorded by the detector. The analyses presented here use the new IceCube Enhanced Starting Track Event Selection (ESTES), which identifies events likely generated by muon neutrino interactions within the detector geometry, focusing on neutrino energies of 1-500 TeV with a median angular resolution of 1.4°. Selecting for starting track events filters out not only the atmospheric-muon background, but also the atmospheric-neutrino background in the southern sky. This improves IceCube’s muon neutrino sensitivity to southern-sky neutrino sources, especially for Galactic sources that are not expected to produce a substantial flux of neutrinos above 100 TeV. In this work, the ESTES sample was applied for the first time to searches for astrophysical sources of neutrinos, including a search for diffuse neutrino emission from the Galactic plane. No significant excesses were identified from any of the analyses; however, constraining limits are set on the hadronic emission from TeV gamma-ray Galactic plane objects and models of the diffuse Galactic plane neutrino flux.


PAST EVENTS:

11:30, Friday, January 31

Use this link to access the meeting: ZOOM


11:30, Friday, January 24

Use this link to access the meeting: ZOOM
Guest: Jianhao Wu (The Chinese University of Hong Kong)

Title: Can blue-tilted primordial power spectrum save the small scale crisis in MW? – From the perspective of Zoom-In simulation for MW host size dark matter halo

Abstract: Recent observations from the James Webb Space Telescope revealed a surprisingly large number of galaxies formed at high redshift. Along with strong lensing studies and nearby galaxy observations, these could challenge the standard Lambda Cold Dark Matter cosmology with a power-law primordial power spectrum. In this study, we conduct high-resolution cosmological zoom-in dark matter-only simulations of Milky Way host size halos with a blue, tilted primordial power spectrum (P(k)∝k^ms with ms>1 at small scales >1 Mpc^1). We find that the blue-tilted subhalo mass functions can be enhanced by more than a factor of two for subhalo masses Msub≲10^10 M⊙, whereas the subhalo Vmax functions can be enhanced by a factor of four for maximum circular velocities Vmax≲30 km/s. The blue-tilted scaled cumulative substructure fraction can be an order of magnitude higher at ~10% of the virial radius. The blue-tilted subhalos also have higher central densities, since the blue-tilted subhalos reach the same Vmax at a smaller distance Rmax from the center. We have also verified these findings with higher-resolution simulations.

11:30, Friday, January 17

Use this link to access the meeting: ZOOM