lit: Verheijen et al, volume complete TFR, also declining rotation curves

see Verheijen et al. article on a volume-complete TF sample.
Also, the references therein, esp. Casertano & Van Gorkom, 1991 for a discussion of declining rotation curves in more massive galaxies.

lit: Velocity dispersions and dynamical masses for a large sample of quiescent galaxies at z>1

By Belli et al. They show that the stellar-dynamical mass ratio for massive ellipticals was in place at z > 1.

lit: Face-on TFR with IFU

Andersen and Bershady 2003

lit: testing CDM with low-mass TFR

Blanton et al. 2008.

Uncertainties are distributions, not errorbar values

This clicked on me while preparing for a talk, though it's an obvious thing: too often we are content with just plotting errorbars and not specifying what do they mean (for instance: 1 sigma-uncertainties, Gaussian distribution). This makes propagating uncertainties (and using the data for model selection) actually impossible.
To put it another way: we don't have datapoints, we operate with slippery, diffuse clouds of probabilities of data. My current task is to take full 2D uncertainties distribution for my datapoints and re-use them in the following steps of hierarchical analysis.

lit: Stellar mass-to-light ratios and the Tully-Fisher relation

I'll have to read this when I get more sleep: iopscience.iop.org/0004-637X/550/1/212

Daily Paper #10: Reconstructed density and velocity fields from the 2MASS Redshift Survey

Today's article was referenced to in the WISE TF paper I summarised yesterday. I wanted to find out how the peculiar velocities and density fields were reconstructed.
Title: Reconstructed density and velocity fields from the 2MASS Redshift Survey
Authors: Erdoğdu, Lahav et al.
Year: 2006, http://mnras.oxfordjournals.org/content/373/1/45.full
I have to admit I did not understand the mathematics of this article, and will read Peebles 1973 and Fisher 1995 to understand what are the spherical harmonics and Fourier-Bessel functions in detail. What they do in order to transform the the redshift space to the real space is decompose the redshift space distribution into radial and angular components. Peculiar velocities affect only the radial component, so it is easier to deconvolve them.
The relationship between mass and light distribution is usually assumed to be linear with some proportionality constant (there is an article by Vivienne arguing that this is not the case).
They provide density and velocity maps up to cz = 16 0000 km/s, which covers the CALIFA redshift range. I could ask them for the velocity data and obtain the peculiar velocities/infall corrected distances for the sample. I think it would be useful for me later, when working with the density fields and spin alignments. We would also have these distances and their errors for all the galaxies, not only the ones identified as belonging to structures.
Previously I used the Virgo-GA-Shapley infall corrected redshifts from NED (obtained using this model: http://iopscience.iop.org/0004-637X/529/2/786/fulltext/). It's a simpler model, taking only these three attractors into account.

Daily Paper #9: WISE TF: A Mid-infrared, 3.4-micron Extension of the Tully-Fisher Relation Using WISE Photometry

Here's the recent WISE paper my supervisor had sent me a link to.
Title:WISE TF: A Mid-infrared, 3.4-micron Extension of the Tully-Fisher Relation Using WISE Photometry
Authors: Lagattuta, Mould et al.
Year: 2013, http://arxiv.org/abs/1305.4637v1
In a way, this is a classic, straightforward observational TFR paper. They pick the shortest wavelength (3.4 um) WISE band, where dust emission is not very important, use archival HI linewidths from Hyperleda and Cornell HI archive and WISE photometry (w1gmag magnitudes). They also take morphological classifications from CfA ZCAT and axis ratios from V-band measurements in NED. They reject galaxies with low quality of radio observations and inclinations (from b/a) less than 45 deg, as well as all E galaxies.
What was interesting for me here was that they did a number of corrections in a thorough way, especially the peculiar velocities correction. Since their and CALIFA redshifts overlap, we might have to give more thought to this correction, as it can reduce scatter in the resulting TFR significantly. They use the Erdoglu 2006 model, interpolating over the velocity grid where necessary (I'll read it for tomorrow).
The intrinsic extinction correction are small in the mid IR, but not so in the SDSS r-band. I'll check Masters 2003 correction prescription too, maybe it's better than the one I'm using.
They also find a bend in their TFR, due to different morphological types -- like we do (the slopes for late and early spirals are different), which is worth mentioning! However, they normalise the magnitudes of the early types and force them to fit the late-type spirals relation. Since our sample is dominated by early-type spirals, I would not want to do that (and I'm not sure what physical basis there is for this correction).
There is a reference to a 2013 paper by Sorce et al., where it is claimed that redder galaxies lie above the TF relation, and the bluer ones lie below, that's interesting.
They also discuss the influence of a bulge to the scatter of TFR, which is larger at the IR and for massive galaxies -- I'll remember that.
What made me think is their conclusion that the mid-IR W1 and 2MASS K bands trace the same stellar populations, a significant fraction of which are in the central parts of the galaxies (thus, probably bulges, esp. in CALIFA sample). That is interesting, in part because we make the inclination and extinction corrections assuming the galaxies are thin disks. Also, we have to keep in mind that when we plot the TFR for different bands, we are relating disk rotation velocities with different morphological components of a galaxy, which do not necessarily correspond to the disk only!

Daily Paper #7: Galaxy groups in the 2dFGRS: the number density of groups

Title: Galaxy groups in the 2dFGRS: the number density of groups
Authors: Eke, Baugh, Cole et al.
Year: 2006, http://adsabs.harvard.edu/abs/2006MNRAS.370.1147E
The authors determine the galaxy groups mass and luminosity functions from 2dFGRS Percolation-Inferred Galaxy Group (2PIGG) catalogue (getting about 29 000 groups). The catalogue and the mock catalogues used to determine and correct for bias are described in Eke 2004 paper.
They obtain dynamical masses of the clusters (I think they use the words 'cluster' and 'group' interchangeably here) from their velocity dispersions, and obtain their luminosities by simply adding up the members' luminosities with weighting to account for spectroscopic incompleteness and galaxies below the flux limit. Then they correct the mass and luminosity functions using the Vmax method. However, they claim that a more robust way to determine the group mass function is deriving it from the luminosity function by multiplying it by a mass-to-light ratio. They also show that the total group luminosity function depends on the group finding algorithm used.
The main goal of the article is to determine the \sigma_8 parameter, but they make a comparison between halo velocities and circular velocities, claiming that the two are similar. The authors claim it is possible to convert a halo luminosity to its circular rotation velocity directly, then convert group luminosities (which are very similar to those of the brightest galaxy of the group) to circular velocities using Bell & de Jong B-band TF relation, and compare the two (see the attached figure).


I think it is an important article, because it is observational, and worth citing while discussing the halo/galaxy velocities issue (the ratio of v_c/v_200 is around 1.2, at least from the simulations, not close to 1 as they find here). Anyway, I'll remember this article in case I have enough time to work on the velocity function.

lit: Asymmetry of galaxies

by Conselice, Bershady et al.

lit: Intrinsic properties of SDSS galaxies

Maller et al.. It's important in many other ways, but here is an interesting excerpt on why TF relation is different:
However, with the notable exception of the Tully-Fisher relation these distributions and relations are traditionally measured in terms of the observed properties of galaxies. That is, the measurements used are K-corrected and corrected for foreground dust extinction, but no correction is attempted to compensate for the viewing angle from which the galaxies are observed. In contrast, the Tully-Fisher relation is not a relationship between a galaxy's observed luminosity and rotation velocity, but a relation between a galaxy luminosity and rotation velocity corrected for inclination. The inclination correction attempts to recover the intrinsic properties of a galaxy and not properties that are measured because of the particular angle from which the galaxy is viewed. For a long time there was great controversy over whether spiral galaxies are optically thin or optically thick (e.g., Holmberg 1958; Disney et al. 1989), but in the early 1990s it was established that galaxies become redder and fainter as they are inclined (e.g., Burstein et al. 1991).

lit: Hubble formula for inclination vs. axis ratio

By S. Van den Berg. Why q = 0.2 is not always a good estimate of the intrinsic thickness.

lit review: The shape of the dark matter halo in the early-type galaxy NGC 2974

The shape of the dark matter halo in the early-type galaxy NGC 2974, by Weijmans, Krajnovic et al. They use kinemetry to analyse gas and stellar kinematics, with clear description of the AD correction. (Thanks, Mariya!)

Jerusalem WS lecture notes: 16. Signatures of Inflows and Outflows

By R. Dave, slides here.

• metals in diffuse IGM -- outflows!
• at high z, SF can't keep up with inflow: the gas accumulation phase: gas can even turn into molecular phase, but due to low efficiency it won't all be processed into stars (equilibrium breaks down), RD 2012
• eta scaling ~ M_{halo} ^{-1/3} -- z_{equil} ~ 5 for massive galaxies
• equilibrium model code at http://ursa.as.arizona.edu/~/rad/work/equil.c
• 'thesis back in the stone age'
• constraining outflow parameters: direct observation and direct modelling are challenging
• direct observation of preventive feedback:
  • mass in CGM: gas in absorption, X-ray emission, soft X-ray bg: COS (Cosmic Origins Spectrograph): OVI high ionisation line, 2 components: photo- and collisional excitation: SF galaxies are probing 300 000 K gas: http://sci.esa.int/science-e/www/object/index.cfm?fobjectid=49663, Anderson 2012
  • direct observations of ejective feedback: outflowing ISM lines: LBG tomography
  • direct observations of wind recycling: _metallicity_ of inflowing gas. Disk outskirts: \alpha_z ~ 0.3
• indirect constraints:
  • counting statistics are not as good as scaling relations
  • galaxies to 0th order are a 1-parameter family (stellar or halo mass) --> good scaling parameters
  • conversion efficiency peaks at 10^{12} M_{\odot}
  • if you don't have winds, you have overcooling problems
  • cosmic SFR efficiency: SFR vs. Halo mass infall rate: a simple combination of model parameters (Behroozi et al), simulations are hard
  • SFR vs. M_{\odot}: galaxy MS is the parameter to compare SF galaxies across redshifts, not SFR -- present starbursts and past normal SF galaxies have identical SFRs
  • MS evolution is currently difficult to model
  • SFR -- metallicity relation
  • M_{star} -- feedback relation
  • M_{star} function -- Baldry 2008 simulations -- reproduces the lower mass GSMF well, arbitrary quenching at logM > 11, governed by differential recycling which flattens the relation at intermediate masses --> inflection
  • gas fractions and X_{co}
• DLAs: kinematics favor ejection, not prevention, CDM has many low-mass halos, if they have many HI, too many narrow DLAs result

Jerusalem WS lecture notes: 15. Star-Forming Galaxies

By R. Genzel, slides here

• ways to look back in time:
  • look-back imaging surveys
  • local stellar archaeology
  • detailed, resolved in situ observations
  • pathologies: Hanny's Voorwerp: radiation echo --> timescales of AGN evolution
• SF in MW:
  • shielded regions, pressure comparable to diffuse ISM, density far above MW mean
  • highly structured, velocity dispersion ~5 km/s (supersonic motions), increases with scale
  • unstable to fragmentation
  • in large scales -- virialised, in small scales -- not --> inefficient SF:
  • MW SFR ~ 3 M_{\odot}/yr
  • Krumholz 2005
  • gas depletion time way smaller than Hubble time -- why stars are still forming: MHD pressure (Alfven) prevents collapse, GMCs are magnetically supercritical, but highly supersonic --> theory and observations tend to support the second explanation
• SF occurs in clusters (70-90%, Lada & Lada 1993), super star clusters with M ~ 10^6 M_{\odot} -- from the collapse of the whole MC
• SF tracers: Kennicutt 1998
  • H\alpha: traces Lyman continuum, issues w/ extinction correction
  • UV continuum: IR fine structure lines, C+ --> easily collisionally excited, in areas that are exposed to UV, OI line
  • mid and far IR: calorimetric method: UV heats dust, reprocessing: FIR is currently the best, esp. due to Herschel
  • radio: FIR-radio relation, works if there is no AGN, evolutionary changes
  • SFH uncertainties: SF tracers are no better than 0.3 dex
• pictures of extinction:
  • 'screen' of dust and gas surrounding SF region
  • 'mixed' -- dust and stars are mixed, high and low exctinction regions: you can observe short and high wavelengths together, Calzetti 2000
• dust extinction: 'greyer' -- less dependent on wavelength
• mass tracers (see the slides):
  • SED fitting: live stellar mass
  • rotcurves: dynamical mass: HI not detectable beyond z = 0.1-0.2 until at least SKA
  • velocity dispersion
  • CO -- variation of X
  • lensing
  • submm dust luminosity (ALMA)
  • uncertain up to at least factor of 2: SFH, IMF, extinction, spatial distribution, kinematics, conversion factors
• gas-SF formation:
  • K-S relation (empirical, simple physical motivation (see slides)), Kennicutt & Evans 2012 review
  • conversion factor: MW factor not appropriate for metal poor galaxies
  • classic papers on SF: 'very good papers were written beyond our event horizon': Kenicutt 1983: infall required for SF over cosmic time
  • spatially resolved SF relation: KS law between H_2 and SFR is more linear -- can we ignore HI?
  • HCN traces very dense regions
  • detection thresholds: stellar surface density
  • KS relation breaks down in scales < 500 pc -- CO and H\alpha are not correlated, due to local evolutionary effects: larger areas are necessary to 'smear out'
  • 'J. Gunn in suit'
• VLT: very thin, large mirror supported by adaptive optics pads
• LBT: thin faceplate on light honeycomb ceramic structure
• Concepts for > 20 m telescopes:
  • aplanatic Gregorian optics
  • 30 m telescope (TMT), EELT (10" FoV, 5 mirrors)
• JWST: 6m, 'Keck in space'
• AO:
  • wavefront sensor
  • deformable mirror
  • guide star | artificial guide stars
  • feedback w/ computer
• IFUs: KMOS
• mm interferometry of cold gas:
  • IRAM Plateau de Bure -- exploration of molecular gas in high redshift
  • ALMA: 0.005" resolution, R = 30 000000

Jerusalem WS lecture notes: 14. Observed galaxies from high to low redshift

By Simon Lilly. Slides here.

• individual & population observations
• evolving population: looks simple
• tracers at EM spectrum
• small FOVs of high-z surveys
• young stars: star formation | old stars: stellar mass
• relative sizes of HST surveys
• cosmic variance in high-z surveys -- zCOSMOS is completely dominated by LSS, related to CF
• larger fields: cosmic variance becomes larger relative to Poisson variance: 10% for COSMOS field
• CV fundamental limitation of high-z statistics
• beam sizes are non-negligible, sensitivity is limited by confusion noise
• lensing bias: amplification, esp. faint sources: change LFs
• the success of photo z's (R = 5 'spectroscopy'):
  • empirical approaches
  • template fitting approaches
  • quite good agreement with spectro z's: why do they work? galaxies occupy a small section of parameter space [eigenspectra]
  • spectroscopic surveys: Baldry picture, density vs. area: SDSS-like survey is impossible in high z
  • sample selection
  • sedfitting.org
  • H-R diagram: cool & dim | hot & dim | cool & bright | hot & bright
  • SFR estimates:
    • UV luminosity is best at high z
    • reddening can be estimated from the UV spectrum shape: it does not depend on the IMF, however, mass does, because it is dominated by low mass stars
    • dust absorption: UV is strongly absorbed by dust, estimation from re-radiated emission at IR
    • other UV proxies: H\alpha, [OII] 3727, radio continuum [empirical!], soft X-ray luminosity -- derived at local z
  • how do we define stellar mass?
  • how do we estimate stellar mass?
    • NIR is dominated by RGs, not tracing stellar mass as such. If SFR is constant, it will be dominated by younger populations. If SFR rises with time, SED becomes dominated by younger stars even in NIR.
    • SED fitting output depends on assumed SFR history, exponentially decaying SFR is not valid for higher redshifts, Lee et al, 2010, ApJ: stellar masses are the most robust, then Zs, ages.
  • FMR -- fundamental metallicity relation, Yates et al., 2 methods of SDSS Z estimation
  • sizes, structures and morphologies:
    • ZEST: introduced ellipticity, allows selecting spirals: we can now do automated morph classification
  • environment:
    • http://www.astro.phys.ethz.ch/ZENS/
    • overdensity field in high z Universe
  • halo masses aredifficult to get for lower mass haloes (M < 10^{14})
  • galaxy mergers, see Lotz 2011:
    • a key quantity: for a given galaxy, what part of the stars was brought by mergers, what part formed in situ?
    • observational bias when visually looking for disturbed objects
    • pairs of objects
  • gas content: limited information at high z
  • gas inflows, gas outflows:
    • spectra stacking -- very high S/N spectra of galaxy population
  • incomplete observations:
    • high z gas
    • DM haloes
    • systematic uncertainties in many key quantities: SFRs, M_{st}, Zs, etc.
  
  

Jerusalem WS lecture notes: 10. Formation and Mergers of Massive black Holes

By Avi Loeb, slides here.

• why most of the matter is not BHs? Due to angular momentum of collapsing matter <- tidal torques from neighbours near turnaround <- non-spherical collapse
• you can check in, you can't check out
• fill the orbit of Earth w/ water -> black hole from a huge swimming pool in space
• pathological point in space-time
• 'string theorists still get paid, get prizes, they give prizes to each other'
• no hair theorem: charge is not important in astrophysics, only mass and spin
• cosmic censorship conjecture (no naked singularities)
• Beckenstein-Hawking radiation: negligible in astrophysics
• whenever there is a horizon, there are quantum fluctuations
• SgrA* 3D star orbits
• horizon commercial
• Broderick & Loeb 2006 - imaging SgrA*, cosmological beaming due to lensing
• BH spin parameter - max value is c, a = 1, normalisation (spin matters!)
• shadow of the BH: the region behind it has its light obscured
• gas is optically thin for wavelengths < 1mm
• ISM does not blur the image due to free e- scattering (turbulence), blurring is smaller than horizon scale
• VLBA can resolve SgrA* and M87 (~10 u-arcsecs)
• the Event-Horizon Telescope
• radio: Fourier space imaging, Broderick, Loeb 2010
• M87: huge BH, jet base images, Doeleman 2012
• feeding BH: MR instabilities, funnel (empty region for outflow, collimated by outflowing jet)
• Eddington limit: Thompson scattering due to luminosity of BH accretion -> outward force, momentum flux, Thompson cross-section. Protons are pulled by gravity create inward force, they are balanced at Eddington luminosity L_E = 1.3x 10^{38} erg/s (M/M_{\odot})
• BH luminosity: L_E x \eta: mass of BH grows exponentially
• Eddington timescale: short, we can grow a small seed to large value quickly. By trapping radiation, timescales shorten
• hot haloes collapse to supermassive stars -> BHs
• 1% of galaxies are quasars, BH mass is way lower than the total mass of the host: why are quasars short-lived? Because they are suicidal, self-regulating their growth, unbinding the gas that is feeding them.
• 10% quasars have jets (are radio loud)
• Binary AGN (Shen 2011)
• BL regions: characteristic speeds ~0.01c, UV radiation is converted into broad line emission
• NL regions: ~1kpc distance, gass is illuminated by quasar
• merger: at some stage, it can have 1 NL region and 2 BL region. Blech, Loeb 2012
• reverberation mapping, Koessis, Heiman, Loeb
• residence time of BHB - types of migration, shrinks the orbit differently from GWs
• Kulkarni & Loeb: excursion set formalism, multiple BHs: 3 body system is unstable (like human beings)
• SF in outer regions of accretion disk - you're likely to make stars - it may explain why quasar spectra have metal lines!
• extreme mass ratio inspiral stellar mass BH or NS [LISA]
• gravitational waves - time-dependent quadrupoles, BH/NS binaries, LIGO, eLISA (detects virtual GWs, generated by people playing WoW) -> precision: 1/1000th diameter of proton
• BH recoils: if the BHs have different masses, they recoil at hundreds km/s - they get out of the galaxy or move away from the center. GW emission is beamed at one direction, momentum is conserved
• > kick, candidate CID-42
• Star clusters around recoiled BHs in the MW halo: ~100 BHs ejected during assembly of MW halo, carrying SCs from cusp of host dwarf galaxy - there should be some unusual clusters in halo clusters, O'Leary & Loeb 2008. Stars are moving around BH Keplerian potential, BH gets a kick, stars may remain bound by E = -1/2 v^2 - GM/r^2 = 0.5(v - v_{kick} - GM/r^2) (vector addition), if E remains negative
• tidal disruption of stars by BHs ('this is an illustration from NASA, so it has no scientific value')
• loss cone: tidal disruption 1/10^{-5}
• BHs larger than 10^8 M_{\odot} swallow the whole stars - Hayasaki, Stone, Loeb 2012
• for binaries: loss cone filled by GW recoil, star disruption once every 10-100 years
• miniquasar 2013 - cloud falling into SgrA*, pericenter of highly elliptical, almost radial orbit with T == 200 yr, imsged in Br\gamma -- Burkert 2012 simulation
• is the cloud pressure-confined? There seems to be no evidence of ambient ram pressure? Maybe this cloud is produced by low mass star with protoplanetary disk - Murray-Clay & Loeb 2012
• hypervelocity planets from tidal disruption of stellar binaries