Frederick Davies

@astro_rameyer @maximetrebitsch 2375 🤪

@maximetrebitsch >2300 😭😭😭😭

Well, it looks like last year's record number of proposals is already broken #jwst #cycle4

This work is complementary to my postdoc Prakash Gaikwad's paper (arxiv.org/abs/2304.02038) using different simulation/statistical methods. Our analyses (more or less) agree! Phew! At this cosmic epoch, the UV background and the distance UV photons travel both increase steeply.

Finally: arxiv.org/abs/2312.08464 My contribution to the XQR-30 collaboration, wherein we constrain properties of the high-redshift (z = 5 to 6-ish) intergalactic medium from the Lya forest using likelihood-free inference.

First: arxiv.org/abs/2312.06747 The IGM damping wing in the first z = 7.5 quasar *might be* contaminated by absorption from foreground z ~ 7.4 galaxies recently discovered by the JWST NIRSpec GTO (arxiv.org/abs/2309.06470)

It's been a while, but it's time for a (somewhat belated) paper day! About a month ago just before the holidays, I ended up submitting 3(!) papers to arxiv in one week, after a very long drought... 🧵

@KnudJahnke @ab_drake Thanks for that! We actually just found out that our Hausarzt is doing a vax campaign (BNT/JJ/AZ) all day on Thursday/Friday, so we’re going to wait in line and hope for the best. Selfishly trying to not miss exciting talks at a virtual conference tomorrow…

MPIA have just come through for us big time 😁. Very lucky to be here.

(nowhere near enough precision for cosmology, though. probably.)

New paper showed up on arxiv this week, arxiv.org/abs/2007.15657. High-z quasar proximity zones probe the intrinsic luminosity, and thus can constrain (strong) gravitational lensing!

New paper on arXiv today! Putting quasar spectral reconstructions to the test. Older techniques have biases & it explains why previous measurements of reionisation disagreed. Newer techniques good (pictured). arxiv.org/abs/2006.10744 w/ @freddavies

@AstroMikeMerri @Unistellar Not at all! It's amazing you could see multiple images of a lensed quasar! One of the previous targets on my quest to detect the most distant objects I could was this z=3.9 lensed quasar, but unfortunately its images are separated by ~0.4" so there was no hope to split them...

@Unistellar @freddavies Makes my observation look quite parochial... youtu.be/nLSBGuPm-DQ

Take a look at the most distant object observed with the eVscope so far! This is a quasar, the extremely bright core of a galaxy that is almost as old as our universe. Many thanks to @freddavies who observed it with his eVscope! buff.ly/2Aug2hJ

Excited to see whether anyone believes our sub-microarcsecond per year precision 🤪

Just arrived in Honolulu for a very brief stop by the AAS meeting. Tomorrow I’m finally giving a talk about the end(?) of my very first astronomy research project, which started back in 2008 and has moved with me around the globe...

@Mirpandaa How about you? I'm always impressed by the design stuff showing up on your instagram!

@Mirpandaa Good! Just moved from Santa Barbara to the Bay area, hanging out in a hotel while my new place gets some maintenance done (move in got rescheduled from the 1st to the 7th, sux). I'll only be here for a bit less than a year, but it should be fun. (The rent is too damn high, tho)

The gist is that the highest redshift quasars seem to have emitted far fewer ionizing photons (factor of >20) than they “should” have. This implies rapid, supercritical growth and/or high levels of obscuration along our line of sight in the past.

Just in time for my talk at EWASS, our paper on the nature of reionization-epoch quasar growth is finally on arxiv: arxiv.org/abs/1906.10130