Question
Mysterious circles of diffuse radio emission called odd radio circles, or ORCs (“orcs”), usually have steep values for this quantity between negative two and negative one. For 10 points each:
[10h] Name this quantity that, for a source with flux density S at frequency nu, is the exponent alpha in the equation “S equals nu to the alpha.”
ANSWER: spectral index [or spectral indices]
[10m] The steep spectral index of ORCs suggests that the source of radio emission is this type of radiation. Relativistic jets emit this type of radiation that is beamed in the direction of motion.
ANSWER: synchrotron radiation [prompt on magnetobremsstrahlung; reject “bremsstrahlung”]
[10e] Observed values for this property’s fractional form show that the tangential magnetic field varies smoothly around an ORC. This property refers to the orientation of the E- and B-fields of light.
ANSWER: polarization [accept polarized light; reject “polar” or “polarity”]
<Other Science>
Summary
| 2024 ACF Nationals | 2024-04-21 | Y | 22 | 12.27 | 100% | 18% | 5% |
Data
| Chicago A | Arizona State | 10 | 0 | 10 | 20 |
| Waterloo | Berkeley A | 0 | 0 | 10 | 10 |
| Brown | Ottawa | 0 | 0 | 10 | 10 |
| Columbia B | Chicago D | 0 | 10 | 10 | 20 |
| Cornell B | Georgia Tech | 0 | 0 | 10 | 10 |
| Johns Hopkins | Duke | 0 | 0 | 10 | 10 |
| North Carolina A | Florida | 0 | 0 | 10 | 10 |
| Chicago B | Harvard | 0 | 0 | 10 | 10 |
| Illinois | Chicago C | 0 | 0 | 10 | 10 |
| Indiana | Iowa State | 0 | 10 | 10 | 20 |
| Berkeley B | Kentucky | 0 | 10 | 10 | 20 |
| Maryland | Truman State | 0 | 0 | 10 | 10 |
| Minnesota A | McGill | 0 | 0 | 10 | 10 |
| WUSTL A | Minnesota B | 0 | 0 | 10 | 10 |
| Toronto B | North Carolina B | 0 | 0 | 10 | 10 |
| Northwestern | Yale B | 0 | 0 | 10 | 10 |
| Stanford | Purdue | 0 | 10 | 10 | 20 |
| Rutgers | NYU | 0 | 0 | 10 | 10 |
| Vanderbilt | Penn | 0 | 0 | 10 | 10 |
| Virginia | Toronto A | 0 | 0 | 10 | 10 |
| Texas | WUSTL B | 0 | 0 | 10 | 10 |
| Yale A | South Carolina | 0 | 0 | 10 | 10 |