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Dr Pamela L Gay #BlackLivesMatter

9 Jun, 10 tweets, 3 min read

First presentation looks at CHIME and Fast Radio Bursts!

Fast Radio Bursts: From a Handful to Hundreds with CHIME/FRB
Kiyoshi Masui (MIT), Alex Josephy (McGill University) & Mohit Bhardwaj (McGill Univ.)

1/

CHIME is a cool Canadian radio array nicely tuned to the colors of radio light where whatever is causing Fast Radio Bursts (FRBs) are doing their primary bursting.

We really don’t know a lot about FRBs. They are (astronomically) pretty new discoveries, every obs is needed.

2/

FRBs are brief, & to see them you need to either be looking exactly right by luck, or looking everywhere by design.

CHIME uses sophisticated data processing to look at most of visible sky simultaneously, and tune in fast.

3/

In just a couple years, known catalogue grew a lot!

(I am really hoping their graphics/animations are made available).

CHIME has created first massive catalogue of where FRBs are, & how intervening matter disperses their light. They let us map them, and the universe between us and them!

My guess: 1 catalog->many(!) papers.

4/

And those papers are starting with Josephy et al. 2021, Rafiei-Ravandi et al. 2021 which look at distribution.

Need to understand if uniformly distributed in sky, & where in distance. The distance tells us when they did / do exist.

Result: They trace largescale structure!

5/

(Apparently I’m just going to use a lot of exlamation marks. I’m kind of excited about this catalogue.)

6/

FRBs come in different forms. Most markedly, there are repeating FRBs and one-off FRBs.

CHIME is finding repeaters tend to have larger widths (in time?) & smaller bandwidths (in color).

So, we’re looking at not just one explanation. Reminds me of the days of chasing GRBs.

7/

To really understand FRBs, we need to find a nearby one…. And it looks like CHIME did: FRB181030A is aligned with the spiral arm of a galaxy 486million ly. and it’s behavior is consistent with this pretty local location.

More data please…. Not enough time in talks :-(

8/

Side note: I’m not sure I’ve ever seen this much chemistry at an AAS planet. Considering planet formation as part of star formation is really messing with our early Hydrogen, Helium, Metals thinking…. so much more chemistry to get at better accurasy.

9/

Ok - the FRB talk ended while I typed, and I missed the transition. WANT MORE.

fini/

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More from @starstryder

Dr Pamela L Gay #BlackLivesMatter

@starstryder

9 Jun

The 2nd presentation in today’s first #AAS238 presser looks at ways to find planets by looking at the composition of stars.

A Statistical Search for Chemical Signatures of Planet Formation in Sun-like Stars
Jacob Nibauer (University of Pennsylvania)

1/

There was a lot of chemistry in this talk, but the bottom line is this: If you have two stars that formed from the same kind of stuff, then the star that forms rocky worlds will have less of the stuff needed to make those planets then a star that didn’t make planets.

2/

To test this concept, need to cross-match Kepler & TESS exoplanet hosts to identify if they do or don’t show expected depletions, need to consider binaries.

I’m curious if we have enough data to consistently say, here are rocky worlds, & here aren’t rocky worlds?

Will ask.

3/

Read 4 tweets

Dr Pamela L Gay #BlackLivesMatter

@starstryder

8 Jun

Ok, seminar stuff about this giant new shiny IR telescope that may or may not launch later this year.

So far, it’s the same info seen since I was in grad school, but with better images & animations.

Reminder, JWST was supposed to launch in 2007.

No, I’m not bitter.

1/

This presentation is acknowledging how ALMA is really doing amazing science that we really thought would have to wait until JWST launched.

Scientists will find a way to science!

This ground-based array is using its limited wavelengths to see star+Planet formation.

2/

From the ground, our atmosphere blocks & blurs many molecular lines - like water - but if JWST works (how do you say “break a leg" in telescope?) it will see more details, & will see what science data is blocked by our atmosphere’s water.

We really need to do IR from space.

3/

Read 14 tweets

Dr Pamela L Gay #BlackLivesMatter

@starstryder

8 Jun

The first presentation of this presser is:

The Molecular Content of Planetary Nebulae: The Next Level
Kate Gold & Deborah Schmidt

and we are starting with super pretty images. I *need* to find this mosaic of Planetary Nebulae.

1/

We know basics of Planetary Neb (PN). Middle mass stars stop fusing materials in their core, exhale their atmospheres into nebulae, & that material gets recycled into future gen of stars. Since the PN are made of material enriched in the star, they have lots of MOLECULES.

2/

In this study, Gold & Schmidt observed a series of PN with different ages to see what is in them over time. They looked specifically for HCN & HCO+ in 30 PN and found they are common & seem to date back to star. This means molecules form in star & survive nebula formation.

3/

Read 4 tweets

Dr Pamela L Gay #BlackLivesMatter

@starstryder

7 Jun

From galaxy mergers we now turn to Black Hole mergers.

TMaximum Black Hole Mass Across Cosmic Time
Jorick Vink

This is a weird system with 2 larger then necassarily steller mass systems merging into an intermediate mass Black Hole!

Q - What is max mass of Star/BH?

1/

It was thought that as steller masses increase, steller winds increasm causing more and more material to be lost through wind, and lower the max mass of the star. BUT… is this always true?

No - stars with lots of metals have more possible spectral lines and lower max mass

2/

On the other hand, if you have very very low metallicity stars - stars missing heavy atoms - then stars can get much much bigger, and bigger black holes can result from the evolution of a single star.

Stars even up to 100 solar masses!

This can lead to the 85 solar mass BH

3/

Read 5 tweets

Dr Pamela L Gay #BlackLivesMatter

@starstryder

7 Jun

Well, I made the release I wanted:

A Merging Galaxy Triple Hosting a Potential Dual Active Galactic Nucleus
Jonathan Williams

Basically - models being done to sort how systems merge and evolve and now compared to Data of 3x merger

1/

This is a striking system. The bright cores are 9100ly apart and appear to be AGN.

The fainter system appears to be a dwarf galaxy that has perhaps already passed between the other two cores.

2/

Specral imaging in Halpha allows velocities to be mapped thanks to the Doppler shifting of the moving gas spread throughout the system.

3/

Read 4 tweets

Dr Pamela L Gay #BlackLivesMatter

@starstryder

7 Jun

Now for release I most looked forward to:

Eta Carinae's Change of State as Seen by Hubble from 1998 to 2021
Kris Davidson, University of Minnesota

Eta Car failed to go SN in the past but will likely go boom in the future. AND it’s only 7500ly away.

1/

Davidson reminds us at #AAS238 presser that Eta Car was one of the brightest stars in the sky… until it wasn’t. In 1800s there was a great eruption but then the star fadded away… only to slowly rebrighten again. It continues to work its way back to bright.

2/

Eta Car is actually 2 stars: a giant & a companion. They orbit every 5.5 yr & have a highly elliptical orbit that causes them to get much closer every 5.5 years. In the past, during this close passing, massive star dumped so much matter on companion it blocked UV.

3/

Read 5 tweets

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