Hubble’s Constant, the Hubble’s Constant, the Oosterhoff Dichotomy and Oosterhoff Dichotomy and

Hydrogen Ionization Fronts. Hydrogen Ionization Fronts.

Shashi M. KanburShashi M. Kanbur

University of Florida,University of Florida,

September 2009September 2009

AcknowledgmentsAcknowledgments Chow Choong Ngeow, Douglas Leonard, Lucas Chow Choong Ngeow, Douglas Leonard, Lucas

Macri, Robert Szabo, Robert Buchler, Marcella Macri, Robert Szabo, Robert Buchler, Marcella Marconi.Marconi.

SUNY Oswego undergrads: Dylan Wallace, Dan SUNY Oswego undergrads: Dylan Wallace, Dan Crain, Greg Feiden, Richard Stevens, Robin Crain, Greg Feiden, Richard Stevens, Robin Dienhoffer, Frank Ripple, Sean Scott, Earl Dienhoffer, Frank Ripple, Sean Scott, Earl Bellinger, Lillie Ghobrial, Mike Evans, Martin Bellinger, Lillie Ghobrial, Mike Evans, Martin Berke.Berke.

Isaac Richter, Tim De Haas, Andy Missert, Isaac Richter, Tim De Haas, Andy Missert, Matthew Turner, Alex James, Eamonn Moyer, Matthew Turner, Alex James, Eamonn Moyer, Jillian Neeley.Jillian Neeley.

NSF, AAS, HST.NSF, AAS, HST.

The Cepheid PL RelationThe Cepheid PL Relation

This relation is not linear – at least in the LMC: This relation is not linear – at least in the LMC: change of slope between short (log P < 1) and change of slope between short (log P < 1) and long (log P > 1) period Cepheids.long (log P > 1) period Cepheids.

OGLE II/III data using OGLE determined OGLE II/III data using OGLE determined reddenings and the Zaritsky reddening map.reddenings and the Zaritsky reddening map.

Need detailed statistical tests for this.Need detailed statistical tests for this. It is NOT sufficient just to look at the slopes plus It is NOT sufficient just to look at the slopes plus

or minus some standard deviationsor minus some standard deviations..

Statistical Tests ImportantStatistical Tests Important

Slope is Slope is ββ±±σσ. This means. This means

P(slopeP(slope is in [is in [ββ--σσ,,ββ++σσ]) = 1 ]) = 1 –– αα..

A = [short period slope is wrong], P(A) = A = [short period slope is wrong], P(A) = αα..

B = [long period slope is wrong], P(B) = B = [long period slope is wrong], P(B) = αα..

P(atP(at least one mistake) = P(AUB) = 2least one mistake) = P(AUB) = 2αα--αα22..

1>1>αα>0, 2>0, 2αα--αα22 >>αα..

P(simultaneousP(simultaneous test makes a mistake) is smaller test makes a mistake) is smaller than than P(standardP(standard comparison makes a mistake).comparison makes a mistake).

Multiphase PL/PC relationsMultiphase PL/PC relations

http://www.oswego.edu/~kanbur/IRES200http://www.oswego.edu/~kanbur/IRES2009/Vphase.mov9/Vphase.mov

http://www.oswego.edu/~kanbur/IRES200http://www.oswego.edu/~kanbur/IRES2009/Iphase.mov9/Iphase.mov

http://www.oswego.edu/~kanbur/IRES200http://www.oswego.edu/~kanbur/IRES2009/Cphase.mov9/Cphase.mov

http://www.oswego.edu/~kanbur/IRES200http://www.oswego.edu/~kanbur/IRES2009/Wphase.mov9/Wphase.mov

LMC testsLMC tests

F test.F test. Schwarz Information Criterion.Schwarz Information Criterion. Testimator plus others.Testimator plus others. OGLE II/OGLE III plus long period Cepheids.OGLE II/OGLE III plus long period Cepheids. MACHO, Sebo et al, Perrson et al.MACHO, Sebo et al, Perrson et al. OGLE II reddenings plus Zaritsky reddenings.OGLE II reddenings plus Zaritsky reddenings. BVIJH non-linear.BVIJH non-linear. K marginally nonlinear. OGLE II Wessenheit linear, K marginally nonlinear. OGLE II Wessenheit linear,

OGLE III Wessenheit marginally nonlinear.OGLE III Wessenheit marginally nonlinear. PL/PC cancel each other out – that is the Wessenheit is PL/PC cancel each other out – that is the Wessenheit is

linear.linear.

JHK DataJHK Data

3 years observing campaign using 1.5m 3 years observing campaign using 1.5m NOAO telescope plus CPAPIR and OGLE NOAO telescope plus CPAPIR and OGLE LMC pointings.LMC pointings.

2 years of Sloan filter data again using 2 years of Sloan filter data again using LMC OGLE pointings.LMC OGLE pointings.

Analyzing this data currently.Analyzing this data currently.

M33 DIRECT dataM33 DIRECT data

Cosmological motivationCosmological motivation

KP measured HKP measured H00 to an accuracy of 10%.to an accuracy of 10%. RiessRiess et al (2009) have measured Het al (2009) have measured H00 to an accuracy of to an accuracy of

less than 5%.less than 5%. Strong prospects exist for further reducing this error rate Strong prospects exist for further reducing this error rate

to remove to remove degeneraciesdegeneracies in CMB based parameter in CMB based parameter estimates.estimates.

Need to get better calibrating relations (LMC or NGC Need to get better calibrating relations (LMC or NGC 4285)4285)

Calibrate Calibrate SNIaSNIa Hubble diagram. OGLE II results in a 1Hubble diagram. OGLE II results in a 1--2% change in H2% change in H00 depending on whether a depending on whether a linear/nonlinear PL relation is used.linear/nonlinear PL relation is used.

With OGLE III, a 5% change.With OGLE III, a 5% change.

Impact on H0Impact on H0

Calibrate SNIa diagram with Cepheids.Calibrate SNIa diagram with Cepheids. μμ00 = = μμVV – 2.45( – 2.45(μμVV – – μμII).). W = V – 2.45(V-I).W = V – 2.45(V-I). There is a difference when used with There is a difference when used with

OGLE III with these data.OGLE III with these data. W is less sensitive to possible changes of W is less sensitive to possible changes of

slope in V and I.slope in V and I. http://www.oswego.edu/~kanbur/IRES200http://www.oswego.edu/~kanbur/IRES200

9/H0impact.pdf9/H0impact.pdf

Mid-InfraRed PL relationsMid-InfraRed PL relations

PhysicsPhysics PL/PC relation connected through the PLC relation.PL/PC relation connected through the PLC relation. PC relation affected through the interaction of the stellar PC relation affected through the interaction of the stellar

photosphere and hydrogen ionization front (HIF).photosphere and hydrogen ionization front (HIF). Engaged: Color of star which is related to the Engaged: Color of star which is related to the

Temperature of photosphere = temperature of HIF.Temperature of photosphere = temperature of HIF. Engaged at low densities: Color of Star is related to Engaged at low densities: Color of Star is related to

temperature of photosphere which is less dependent on temperature of photosphere which is less dependent on period.period.

Engaged at high densities: more sensitive to period.Engaged at high densities: more sensitive to period. Sudden: - either engaged or not.Sudden: - either engaged or not. ML relation affects phase/period of interaction.ML relation affects phase/period of interaction. Flat PC relation at maximum light for Galactic Cepheids, Flat PC relation at maximum light for Galactic Cepheids,

and for logP > 1 for LMC Cepheids.and for logP > 1 for LMC Cepheids.

PC/AC RelationsPC/AC Relations

LLmax max ~ R~ R22maxmax T T44

maxmax, L, Lminmin ~ R ~ R22minmin T T44

minmin

Amplitude ~ 4log(TAmplitude ~ 4log(Tmaxmax – T – Tminmin).).

PC relation flat at maximum light – AC PC relation flat at maximum light – AC relation at minimum light and vice versa.relation at minimum light and vice versa.

See this in LMC OGLE II/III Cepheids.See this in LMC OGLE II/III Cepheids. http://www.astro.umass.edu/~shashi/paperhttp://www.astro.umass.edu/~shashi/paper

s/paper1.pdfs/paper1.pdf

RR LyraesRR Lyraes

PC relation at minimum light is flat.PC relation at minimum light is flat. Higher amplitude RR Lyraes are driven to hotter/bluer Higher amplitude RR Lyraes are driven to hotter/bluer

temperatures/colors at maximum light.temperatures/colors at maximum light. PC relation is flat at minimum light because the HIF is PC relation is flat at minimum light because the HIF is

further out in the mass distribution.further out in the mass distribution. HIF always engaged with stellar photosphere for RR HIF always engaged with stellar photosphere for RR

Lyraes.Lyraes. But density changes as pulsation proceeds from But density changes as pulsation proceeds from

minimum light.minimum light. http://www.astro.umass.edu/~shashi/papers/paper9.pdfhttp://www.astro.umass.edu/~shashi/papers/paper9.pdf

The Oosterhoff DichotomyThe Oosterhoff Dichotomy OoI: <P> ~ 0.65 days, Z = 0.001OoI: <P> ~ 0.65 days, Z = 0.001 OoII: <P> ~ 0.55 days, Z = 0.0001OoII: <P> ~ 0.55 days, Z = 0.0001 Period-Amplitude (PA) relation different in the Period-Amplitude (PA) relation different in the

two groups.two groups. Evolved RRab stars in OoI clusters follow a Evolved RRab stars in OoI clusters follow a

similar PA relation to that in OoII clusterssimilar PA relation to that in OoII clusters M3: OoI, M15: OoII.M3: OoI, M15: OoII. V = a + blog PV = a + blog P V = a + c(B-V) – c(B-V) + blogPV = a + c(B-V) – c(B-V) + blogP Related to PC/AC relations as a function of Related to PC/AC relations as a function of

phasephase

M3/M15 analysisM3/M15 analysis

M3 data from Benko et al (2007)M3 data from Benko et al (2007) M15 data from Corwin et al (2008)M15 data from Corwin et al (2008) Fourier decomposition to smooth out observed Fourier decomposition to smooth out observed

data.data. Use decomposition to estimate max/min.Use decomposition to estimate max/min. BVI light curves.BVI light curves. Concentrate on RRab stars.Concentrate on RRab stars. Possible evidence of a difference in PC/AC Possible evidence of a difference in PC/AC

relations as a function of phase.relations as a function of phase.

PC/AC relations in RR LyraesPC/AC relations in RR Lyraes

Sloan RR Lyraes and M31 data usign HST.Sloan RR Lyraes and M31 data usign HST. Theoretical models computed by Robert Szabo.Theoretical models computed by Robert Szabo. M,L,T,X,Z. Two values of Z=0.001, Z=0.0001M,L,T,X,Z. Two values of Z=0.001, Z=0.0001 Range of M/L. Strong possibilities to constrain Range of M/L. Strong possibilities to constrain

models and estimate reddening.models and estimate reddening. Kurucz atmosphere parametrized by effective Kurucz atmosphere parametrized by effective

gravity and photospheric temperature.gravity and photospheric temperature. Comparing models with observations and Comparing models with observations and

understanding possible implications.understanding possible implications.

Model ResultsModel Results