Series: Astronomy Colloquium
Date: Wednesday 05-Oct-2022
Time: 16:05-17:00 (4:05-5:00 pm)
Location: ATL 2400
Speaker: Dr. George Younes (GSFC)
Title: Magnetars: a cosmic physics lab
Magnetars form a sub-population within the isolated neutron star zoo, occupying a unique parameter space in the famed p-pdot diagram. Assuming magnetic dipole radiation, their inferred magnetic fields are on average two orders of magnitude larger than regular pulsars. This immense reservoir of magnetic energy fuels their bright persistent surface thermal, and magnetospheric non-thermal X-ray emission. It is also the driver of sub-second soft gamma-ray flashes, giant flares (brightest X-ray events detected, after the sun), and years-long outbursts during which extreme variability is observed; altered spectral and pulse shapes, glitching activity, strong timing noise, appearance of radio activity, among other attributes. All the above relate to the dynamic internal structure of these sources, the way in which that impacts the exterior through twisted field lines, and the influence of the high B-field on the observed electromagnetic radiation. Additionally, the large energy stock of magnetars is commonly invoked as a power source for other extreme transient phenomena, such as gamma-ray bursts, superluminous supernovae, ultra-luminous X-ray sources, and finally fast radio bursts (FRBs). Smoking-gun evidence for the latter occurred on 2020 April 28, when an FRB-like radio burst was simultaneously detected with an X-ray burst from the Galactic magnetar SGR 1935+2143. In this talk, I will summarize the latest high energy observational results from a few Galactic magnetars, their relation to FRBs and other extragalactic phenomena, and their strength in providing great insight into neutron star physics and radiative processes in high B-field regime.
In-person colloquia are usually preceded by espresso and ice cream at 1:45 pm outside room PSC 1150 and are followed by an informal reception at 5:15 pm in that room. Anyone interested in talking with the speaker, or being added to the colloquium announcement email list, should contact the colloquium organizer Dr. Leslie Sage. Lunch will normally be reserved for the speaker to talk to graduate students. Anyone asking a question during a talk is asked to raise their hand and be acknowledged before speaking. Contact Dr. Leslie Sage for details.
Colloquium Organizer:
Dr. Leslie Sage
Special accommodations for individuals with disabilities can be made by calling (301) 405-3001. It would be appreciated if we are notified at least one week in advance.
