BE VERY AFRAID

BE VERY AFRAID

Cosmologia en la Playa 2010

Supernovae and the Accelerating Universe

Nicholas B. SuntzeffMitchell Institute for Fundamental Physics & Astronomy

Department of Physics & AstronomyTexas A&M University

University of Texas/Austin

14 January 2010

How cosmology used to be done: Historical Visit of Einstein to Mt. Wilson

Al Einstein

George Ellery Hale

Ed Hubble

Milt Humason

Chuck St. JamesWalt Adams

lots of books

The sad reality of cosmology today:Unhistorical Visit of Suntzeff to Mt. Wilson

Suntzeff

Gaston

Folatteli

Mark Phillips

George Ellery Hale

Same books =>

can’t get no respect…

SN1994D

Supernovae!

P. Challis

CfA & NASA

SN spectra

Type Ia

Core

Collapse

Type Ib/c &

Type II

SN SEDs

Ia

Ib/c

II

General light curves56Ni 56Co 56Fe

Leibundgut & Suntzeff

98

delta m15

Suntzeff (1996)

Phillips (1993)

Calan/Tololo survey

1990-1996One parameter

family

Color

Rate of decline

Peak brightness

Secondary max due to Fe++

Fe+

mystery - where is Fe+ Fe0 ??

Absolute magnitudes of Type

Ia SNe

H, K probable standard candles,

Krisciunas etal 2003.

brighter

Effects of correction

to m15

brighter

fainter0.2 magPeak effect for

L is at about z~0.8.

We are looking for

about a 0.25m effect.

Distance Modulus II

Equation-of-State Signal

Difference in apparent SN brightness vs. zΩΛ=0.70, flat cosmology

Assume P = wc2

The ESSENCE SurveyDetermine w to 10% or w!=-1

6-year project on CTIO/NOAO 4m telescope in Chile; 12 sq. deg.

Wide-field images in 2 bands

Same-night detection of SNe

Spectroscopy

Keck, VLT, Gemini, Magellan

Goal is 200 SNeIa, 0.2<z<0.8

Data and SNeIa public real-time

ESSENCE Survey Team

Claudio Aguilera CTIO/NOAO Bruno Leibundgut ESO

Andy Becker Univ. of Washington Weidong Li UC Berkeley

Stéphane Blondin Harvard/CfA Thomas Matheson NOAO

Peter Challis Harvard/CfA Gajus Miknaitis Fermilab

Ryan Chornock UC Berkeley Jose Prieto OSU

Alejandro Clocchiatti Univ. Católica de Chile Armin Rest NOAO/CTIO

Ricardo Covarrubias Univ. of Washington Adam Riess STScI/JHU

Tamara Davis Dark Cosmology Center Brian Schmidt ANU/Stromo/SSO

Alex Filippenko UC Berkeley Chris Smith CTIO/NOAO

Arti Garg Harvard University Jesper Sollerman Stockholm Obs.

Peter Garnavich Notre Dame University Jason Spyromilio ESO

Malcolm Hicken Harvard University Christopher Stubbs Harvard University

Saurabh Jha SLAC/KIPAC Nicholas Suntzeff Texas A&M

Robert Kirshner Harvard/CfA John Tonry Univ. of Hawaii

Kevin Krisciunas Texas A&M Michael Wood-Vasey Harvard/CfA

ESSENCE Summary

200 SNeIa from 2002-2007

200 good light curves (Wood-Vasey, et al 2009)

Data from Keck, Gemini, VLT, CTIO, HST

GoldUnionConstitutionwhat the **** set

SDSS SN plot

Lesson in plotting

Being from Texas, I suggest

the Confederate Set is next

Carnegie Supernova Project

• Phillips, Freedman, Hamuy, Madore, Burns, Follatelli, Cadenas, Suntzeff

High-z project

I-band measurements

Cosmology fits

Carnegie Low-z Sample• 5-year project, 270n per year on 1m Swope + nights

on Magellan, du Pont, VLT

• Ending 2009 (around now)

• ugriBVYJH(Ks). Ks with WIRC on duPont

• Spectra where we can [more hot spectrographs on 2m telescopes are needed]

• Follow all types with z≤0.08 (if caught early)

• 200 Sne with 100 Type Ia

What we are trying to do

• So many data samples with so many methods of analysis have confused us

• We want to “rewrite” history, that is, start with a clean data set and redo our analyses to find the weaknesses of our techniques.

• Purely phenomenological guided by simple physics

• Basic parameter - m15, measured from the light curves, NOT from a black box program

• Measure photometry in the natural system with measured precise transmission functions

• Ultimately the goal is an accuracy of <1% in distance for cosmology with no systematics.

Summary of Sample

First ReleaseContreras, C. et al 2009 arXiv:0910.3330V1

35 Type Ia, 5559 ugriBV optical , 1043 NIR YJHKs

Natural System

Definition of photometric

zero-points

Second Parameter

Same

m15

The secondary maximum is not tightly correlated with the peak luminosity.

Bolometric light curves

Reddening

RV = 1.7 or 3.1??Wang, Goobar

suggestion

Distances to 3%

Hubble Diagram

z=0.001

m=0.12

Hicken et al 2009

A difficult diagram to understand

2 separation between blue

and orange points??

Flux calibrationsFlux calibrations

Bias in distance determination codesBias in distance determination codes

ExtinctionExtinction

Host galaxy

Our Galaxy

Atmosphere

Extinction law

Passband errorsPassband errors

K corrections

Photometry normalization

Nonlinearity in flux measurementsNonlinearity in flux measurements

Potential sources of systematic errorPotential sources of systematic error

More Potential More Potential Systematics Systematics

• “ “Hubble bubble” troubleHubble bubble” trouble

• Gravitational lensingGravitational lensing

• Evolutionary effects in SNeEvolutionary effects in SNe

• Biases in low redshift sampleBiases in low redshift sample

• Search efficiency/selectionSearch efficiency/selection

(Wood-Vasey et al., 2007, ApJ)

SNe and GRB’sWright (2007)

Higher-Z SN Team

Riess, et al

(2007)

Summary

The accelerating Universe poses a significant challenge to theory, experiment and observation.

Current goal: w to 10%

The SNIa data are consistent with a flat Universe with a cosmological constant.

Closing thoughts

• The scale of dark matter

• DETF and future measures of dark energy

• The Hubble constant

• Why are we wasting our time with w’???

• Why are there only 4 techniques?

• We need people to create realistic error models.

Okay, no questions

Come up to the front, leave your computers behind, and let’s talk what it means to be a successful researcher.

(ESA)

(JAXA)(ESA)

46

Astrophysics Division Missions

Astrophysics FY2010 President's Budget andEstimates for 2011 - 2023

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$M

Future Missions

Form, Dev & OpMissions

Mission Enabling

Program Mgmt &Other

• Assumed operating missions beyond 2016 include JWST, SOFIA

• HST De-orbit mission development ramps up ~2020

• “Future Missions” wedge would be used for new mission initiatives, R&A/technology augmentations, extended missions, etc.

• The amount of “Future Missions” funding available between 2013 – 2020 is ~$4B

Budget Guidance for Decadal Survey

• Assumed operating missions beyond 2016 include JWST, SOFIA; plus HST, Chandra, Fermi, etc. (e.g., Astro-H)

• HST De-orbit mission development ramps up ~2020

• “Future Missions” wedge is for strategic missions recommended by the Astro2010 decadal survey

• The amount of “Future Missions” funding available between 2013 – 2020 in such a scenario would be ~$2.3B

Budget Guidance for Decadal Survey – Notional

scenario

• 160 PhD’s per year, 35 permanent positions per year• NASA science sees declining budgets• NSF at best is flat• DOE may step in?• Job register has ~100 postdocs and ~16 faculty positions• US budget is now heavily encumbered with future payments• Obama loves science, but don’t assume that will go to basic science except in green and health science• you probably will not live where you want to live

The bad news

The good news• everyone loves astronomy• it ain’t a lot worse than in 1980• in the past, most people who stuck it out got good jobs

So what to do?• don’t keep on doing your thesis over and over again• establish prominent collaborators and mentors, but appear independent• publish, publish, publish. Include useful tables of summary and colorful figures that can be easily captured.• apply for external funding• luck verus hard work• become the leader in your field• think carefully about joining large projects with time scales of > 5 years.• Spergel’s law• don’t be afraid to go out on a limb and say something weird. • The Aaronson effect in obsevations• When you apply for jobs, make sure you know all about the department – and brown nose a bit. Write your application as if there is no other job out there. Know your audience.•