Texas2019 Notes

Texas2019 Notes.md

Texas 2019 Notes

By: Nathaniel Starkman

EHT Plenary Lecture

• Many SMBHs do not have an accretion disk, but rather a large gas structure. Mostly radio emission. Self-absorption synchrotron radiation.
• When look in millimeter see the BH because dust is very wavelength sensitive
• So much data had to physically ship the data (5 petabytes in 5 days)
• From data to image: pixel-based model where each pixel is a free parameter
  • minimize $\chi^2$ for sum of all pixels
  • find BH, accretion disk, N-S asymmetry
  • The smaller structure in the image shouldn't be taken too seriously

3 characteristic distances:

1. event horizon
2. ISCO (innermost circular orbit)
3. photon radius

Kerr BHs have almost perfectly circular shadows because the spin quadruple is balanced by frame dragging until spin $\sim 0.95 c$.

BH images allows test of no-hair theorem by measuring the circular symmetry. Quadropole doesn't cancel frame dragging.

SMBH Plenary Lecture

Chris Reynolds

potential of x-ray studies and axions

Selection effect: might only see AGN with rapidly spinning BHs because luminosity efficiency for flux-limited survey.

axions

• fun fact: axions named for the detergent because "cleaned" strong CP problem
• gravitational "atoms" with axions. Get orbitals and super-radiance from spin-E
• light bulb. axions-$\gamma$ conversion/absorption

Quasars in Early Universe

Whalen

JWST will be sensitive enough to detect every stage of primordial quasar evolution. Stellar, Direct Collapse BHs, & SMBHs

Quantized Primordial Power Spectrum

Will Handley

PS problems: $\ell=20$ feature, high-$\ell$ oscillatory residual

What is Quantized PS? $\bar{k}$ not continuous Want quantized $\bar{k}$ even when not in closed universe (can naturally occur) get really good fit for some $k_0$ and $\Delta{k}$, when evaluate on a grid but 2 new parameters -> lower BIC Having the Penrose conformal boundary & imposing some BECAUSE means quantized $\bar{k}$ & right OOM horizon shrinks during inflation

Local Universe w/in $\Lambda$CDM

XMM cluster survey. ~1000 day footprint.

• miscentering: bright star or poor fit red sequence
  • x-rays give better centers
  • mot model as having well and poorly centered clusters -> 1 error source in param estimations
• Tx-richness relation ?
• red-mapper selection elongated along LOS

Non-linear Gravity & Cosmology

Jim Merten

Really cool. Averaging procedures get rid of / don't take into account some of physics. Does full-GR simulations to properly understand influence of non-linearities.

Chameleons in Streams

Aneesh Naik

Important

Chameleon 5th force. 2 effective parameters: $\beta$ ($F_S \propto 2\beta^2$) & $\chi_0$ (efficiency)

Burrage and Sakstein 2018 review paper

$\Phi_{eff} \underset{G\rightarrow G'=(1+2\beta^2)G)}{\rightarrow} -\frac{G'M}{r^2} - \frac{G' M_{sat}}{|x-x_{sat}|} - \frac{G' M_{tot}r^2}{2 r_{sat}^3}$

rescale $\phi_{eff} \rightarrow L$ unchanged but scatter more into trailing arms

even when $90%$ screened, still get strong stream asymmetry.

smoggy package on GitHub

GW170817

Kilonova, r-process strontium enrichment Get an amazingly simple power law spectrum, especially as the kilanova fades Use local density measures to break $\rho/E$ degeneracy & get $E\sim 10^{49}$ erg

Binary NS GW -> EOS

Binary NS $\rightarrow$ hyper-massive NS $\rightarrow$ BH + torus GW spectroscopy during HMNS merger event

Non-linear gravity in Cosmology

Tom Giblin

Gravity works great except DM, DE, Inflation. LOL. Gravity is non-linear. It moves power between scales. How important are the effects?

ex: golf ball dimples appear to be a tiny perturbation but massively change how a golf ball flies on scales much larger than the dimples

Are perturbations in cosmology truly "small"? Or are they like golf ball dimples? This is very related to Jim Merten's Averaging Problem.

Do full GR simulations. Can only solve GR with right gauge choice & add stability for numerical sims.

In a sim get $\sim 2%$ difference in expansion rate, even for perfectly homogenous universe.

Hard to make observables because coordinate systems don't really compare to FLRW simple metric. Only see $\lambda$, need to back out observables. It does average to FLRW at large distances.

Test how much linearized Einstein's equations violate GR even for small (?) perturbations.

PBHs from inflation, etc, depend on size of Newtonian potential. But have to confirm this by checking with full non-linear GR.

Signatures of PBHs

Juan Garcia-Bellide

Paper: JBB & someone (2017) for PBH mass ranges

Curvature can induce forces > radiation pressure. The PBH mass strongly depends on the e-fold time of production. $M_{PBH} \approx 30 M_{\odot} e^{3(N-36)}$

doesn't predict uniform distribution or monochromatic PBHs! Instead, predicts clusters of PBHs with wide-mass range.

Higgs inflation: $\mathscr{L}' = \mathscr{L} + \xi |\phi|^2 R$ Negligible on Earth but dominates early universe

Still need to overcome thermodynamics and collapse BHs. If near critical then at QCD scale. Lose radiation pressure for a bit & collapse $\rightarrow$ PBH mass spectrum. Mostly @ $10 M_\odot$.

Paper: Carr & JGB 2019

test with long duration microlensing events. The PBHs are nearly spinless.

Early galaxy formation. Massive PBHs cluster & merge. Expel stars $\rightarrow$ large $\frac{M}{L}$ like in dwarf spheroidal galaxy.

MW Rotation Curve in GDR2

I don't believe this. Use GDR2 positions & solve linearized Einstein's equations. Claim that frame dragging gives flat rotation curves and don't need any DM in the MW. 2018 paper Same fit quality as MW2014 Model ‽‽

LISA

Flena Russi Trail the Earth @ $60\degree$ inclination

Measurement principle: proper time between free-falling masses. Arms are not the same length -> time delay interferometry.

LISA limiting noise: ability to keep arm lengths the same while in freefall.

Most sensitive to SMBHs. Longer period. See $10^{6} - 10^{7} M_{\odot}$ BH up to cosmic dawn.

Use Was to trace baryonic matter in local group. See through galaxy to other side of bulge. Equivalent to $m_{gaia} \sim 70$.

Map out bulge to $%$-level.

Generate $\sim50 M_{\odot}$ BH from Stars

Big stars to big BHs. Biggest star is $300 M_{\odot}$, $10^{6} L_{\odot}$. Huge ionizing region.

For $M \gg M_{\odot}$, $L\not\propto M^3$ but $L\proptoM$ Mass loss is so strong that don't get $M_{PBH} \sim 50$ Got to lower Z to reduce solar winds and get big enough $M_{PBH}$. But pair instability can also drive mass loss. Oxygen burning @ E to produce $e^{-}e^{+}$ pairs. Get explosive O, Si burning.

Pulsation pair instability:

• instead of blowing up, it oscillates with increasingly small explosions until get to Fe burning.
• Therefore, was BH mass $\sim M_{\odot}$
• This was for He stars, not including the H envelope.

Cosmic Concordance Tensions

Anthony Lewis Concordance, standard definition Polarization PS will measured ?

$100 \theta_s$ extremely well measured $\rightarrow \Omega_b$ by PS even-odd peaks. Add in BBN to confirm.

Lithium $5-\sigma$ tension.

$H_0$ from BAO in LSS or sound horizon scale.

Calibrate SN by cepheids.

CMB lensing also gives $68\pm0.7$ Quasar strong lensing gives 73.

How to solve the $H_0$ tension?

• Could lower the sound horizon by $10%$. pre-recombination shenanigans.
• Local neighborhood problem?
  • But HoliCow not local
• Or $8%$ DE @ $M=\gamma$

Cobaya code getdist code has new version

Shape of Universe

Glenn Starkman Extrinsic curvature universe can still be flat

Thurston geometric conjecture: Flat, $S^3$, $H^3$.

topology in CMB:

• discrete modes
• spectrum = topology

challenge: measuring spectrum from 2-slice

Looking for topology in CMD:

1. Correlation function, pixel-by-pixel
2. match circles on the CMB sky

Large Scale Anomolies:

• low-l anomolies ($C(\theta)=0$)
• alignment problem

Absence of 2PCF doesn't match theory at all!

Even drawing "directly from data" doesn't give 0 correlation (only $3%$ of time)

Topology couples eigenmodes and then lose $C(\theta)$ correlation.

Multipole vectors

Strong-Lensing SN

Matt from .Astro

HoliCow $2%$ @ 6 QSO's. Add some more and will nail down $H_0$.

Mass-sheet degeneracy for lens models. Break with SN since standard candle. Predict LSST have $50/yr$. Plenty of data.

Get scatter from microlensing of SN by individual stars. But can find/standardize many to intrinsic noise levels. $\sim 20%$ can be standardizable.

Too faint for day 0 observation in T1B SN

DM & First Stars

Rennan Burkana Ts (21 cm)

2 effects:

1. $T_s \rightarrow T_{CMB}$
2. 1. $T_s \rightarrow T_{gas}$

Wouthusyen 1952, Field 1958

Up then down but not always to same spin state. $n=s \rightarrow n=1$

EDGES: synchrotron + signal $\rightarrow$ 21 cm + noise $\rightarrow$ 21 cm

How solve?

• Solve DM cooling gas by coupling $\propto v^{-4}$
• radio excess to that $T_{CMB} \rightarrow T_{CMB} + T_{r, extra}$

High-E cosmic rays $(>10^7 ev)$

Many different scenarios for GZK cutoff

The sources need to put out a significant fraction fo their energy in Ultra High Energy Cosmic Rays. Not realistic ?

Can get less extreme sources if CRs have high charge, like Fe.

Open Problems in Cosmology

Jo Silk

Black Swan test, differences in perspective between physicists & cosmologists.

DE

converging on Lemaitre GM fluctuation model ($\Lambda$=constant) problem! is there new physics?

DM

Hope for direct detection. Galaxies have $\gamma$-excess in center see in LHC?

Strategies

• look again
  • WIMP window, but closing in without direct detection
• PBH, axions, etc. Alternate DM models not well constrained.

$H_0$ tension systematics? Cepheid environment systematics? Or age problem (since close SN are young and far SN are age-mixed)?

Dwarf Galaxies

Mysteries: numbers, cores, too big to fail, diversity, etc. Solutions: complex feedback? Find via better sims or need new physics?

WDM, can make early galaxies? FDM?

Giant Galaxies

Obesity: SMBH too big. Massive galaxies form too early ($z\sim 6$) Anorexia: nearby galaxies are thin. Particle physics predicts big bulges.

Simulations

Subgrid physics from local universe. But does this apply to early universe?

Where Next?

Inflation Dark Ages. Precision because many more modes. Universe curvature and topology Planck lensing promen

Galaxy Center

FERMI excess $\gamma$-rays INTEGRAL 511 keV excess

Voyager's too low ionization (WHAT IS THIS?)

Dark Shards

the sausage

Far Side of Moon

Lets build detectors. Hell yes. 30 MHz test for primordial non-gaussianity