Transcript Poster Presentations

Focus Meeting 7
Poster Presentations
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Alessandro Bressan
Chen-Hung Chen
Van Dixon
Jesus Gallego
Bob Gehrz
Ylva Goetberg
Jose Groh
Zhanwen Han
Sara Heap
Anne Jaskot
Jakob Ostrowski
Dorottya Szecsi
Grazina Tautvaisiene
Thermal and Non-Thermal Radio Emission in young star
forming metal poor galaxies (Obi*1, A. Bressan1, F. Perrotta1,
Y. Chen1, P. Marigo2, A. Slemer2, L. Silva3, G.L. Granato3, O. Vega4
)New PARSEC evolutionary tracks (FM7p.03 Chen et al.)
SSPs with Nebular Emission (CLOUDY)
GRASIL (Silva+98, Bressan+02, Vega+08) code:
1)Star +dust; 2) thermal radio emission; 3) non thermal radio
emission (includes effects of Failed Sne: Radio Sne > 7Myr)
Figure 2: Bi-parametric criterion for explosion (Ertl et.
2015) applied to models evolved with MESA (Paxton et al.
13) + mass-loss prescriptions of PARSEC
Figure 3 : Thermal (FF), Non Thermal (NTh) and SNR Radio
Emission in SSPs . Note the effects of Z and of Mmax on FF emission.
At 1.4GHz, FF emission for Mmax= 120 M⨀ is 3 - 7 times larger than
for Mmax= 40 M⨀.
NTh emission is almost unchanged because stars with M>30 Mʘ
collapse to BH !
Figure: the GRASIL SED fits to
NGC4536, a galaxy with Z~0.0044.
IMF: two-power law
0.1-1Mʘ : a=-1.4 ;
1.0-Mmax : a=-2.35;
Mmax= 40, 120, 350 Mʘ
With Mmax= 120M⨀ (upper panel)
the model reproduces the observed
Hα luminosity (~1E41 ergs/s) and
the MIR-FIR SED. However radio
emission shows to much FF
contribution.
The case with Mmax= 40 M⨀ nicely
reproduces the radio SED but its
Hα luminosity is 25% lower, as well
as the 24mm flux. Decreasing the
obscuration
of
the
young
component
would produce
a
higher UV and a lower 24mm flux.
The latter could be cured by a weak
obscured AGN (Satyapal et al. 08).

NGC4536
A consistent panchromatic set of SFR indicators is needed, and now available, to
decipher galaxy properties.
FM7 P.06
Chen-Hung Chen1 and Chung-Ming Ko2
1Department
of Physics, National Central University, Taiwan
2Institute of Astronomy, Department of Physics and Center
for Complex Systems, National Central University, Taiwan
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We select elliptical galaxies (fracDevg,r,i = 1) from the
Main Galaxy Sample in Sloan Digital Shy Survey
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Selection criteria are
 Velocity dispersion larger than 50 km/s
 𝑅𝑔 and 𝑅𝑟 > 1.5’’
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We use Herniquist model and Modified Newtonian
Dynamics (MOND) to estimate the stellar mass of galaxies
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
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We use
𝑅𝑔
𝑅𝑟
− 1 to define our color
gradient (Roche et al. 2010, MNRAS,
407, 1231).
Define red-cored / blue-cored galaxies
as
𝑅𝑔
±
−1 >0
𝑅𝑟
Stellar-mass-to-light ratio is linearly
related to color gradient
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At z>0.05 the distribution of mass-tolight ratio ratio of the two samples are
similar.
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At z<0.05 the mean mass-to-light ratio
of the two samples are small,
extremely for blue-cored sample.
Thank You for Your Attention
FUSE, STIS, and Keck Observations
of the UV-Bright Star vZ 1128
in the Globular Cluster M3
Van Dixon & Pierre Chayer
Space Telescope Science Institute
Baltimore, Maryland, USA
Chayer, P. et al. 2015, MNRAS, 452, 2292
UV-bright stars lie above the
horizontal branch and blueward
of the red-giant branch.
The UV-bright star in M3 is
known as vZ 1128 (von Zeipel
1908).
Figure from Moehler 2010
Keck
HIRES
STIS
FUSE
Stellar Rotation
Microturbulence
No additional
broadening
Metal abundances of
vZ 1129 are consistent
with those of stars on
the RGB.
The star’s low carbon abundance implies that vZ 1128 left the AGB before
the onset of thermal pulsing, third dredge-up, and envelope ejection.
Low-mass Star-Forming Galaxies
at intemediate redshifts (z<1)
Jesús Gallego, Lucía Rodríguez-Muñoz (Ph. D. Student)
Collaborators: C. Pacifici, L. Tresse, S. Charlot, A. Gil de Paz, G. Barro, V. Villar
Motivation: Dwarf galaxies as key players in galaxy formation
but Not properly known at cosmological distances
Data:
GOODS Multiband photometry (40 bands) UV, HST, nIR
VLT/MOS+GTC/OSIRIS deep (I=25) spectroscopy
Goal:
Physical properties, Evolution
Star-Formation Histories (see Gallego‘s poster)
MB,0
Z spec
Z spec
Contributions of Classical Novae to the Interstellar Medium
Robert D. Gehrz1, Aneurin Evans2, Charles Woodward1, L. A. Helton3
1Minnesota
Institute for Astrophysics, University of Minnesota, USA
2Astrophysics Group, Lennard Jones Laboratory, Keele University, UK
3USRA/SOFIA, NASA Ames Research Center, USA
We describe infrared (IR)
spectroscopic observations
of gas emission lines and
dust features in the ejecta
and show how abundances
of material injected into the
ISM can be determined.
IR Observations of CNe in the SOFIA Era
H emission
V339 Del
Dust emission
V5668 Sgr
Ionising photons from binary products
7 M⊙
FM7p.10
Ylva Götberg
Anton Pannekoek Institute for Astronomy, Amsterdam University
number of hydrogen ionising photons per
second
Ionising photons from binary products
population with
binaries
population with single
stars
FM7p.10
Ylva Götberg
Anton Pannekoek Institute for Astronomy, Amsterdam University
number of hydrogen ionising photons per
second
Ionising photons from binary products
Did Massive Binaries
contribute to the
population with
Epoch of Reionization?
binaries
Ylva Götberg, Selma E. de Mink & Pablo Marchant
population with single
stars
FM7p.10
Ylva Götberg
Anton Pannekoek Institute for Astronomy, Amsterdam University
Spectroscopic evolution of massive stars from unified stellar models
Groh+ 2013a, A&A 550, 7; Groh+ 2013b, A&A 558, 131; Groh+ 2013c, A&A 558, 1; Groh+ 2014, A&A
564, 30
Jose Groh (Geneva Observatory, Switzerland)
Collaborators
Georges Meynet + Sylvia Ekstrom (Geneva), Cyril Georgy (Keele)
Motivation: Understand how massive stars evolve and die
How? Improve the comparison between models and observations
massive stars:
high Mdot (evolved)
low-mass stars
(e.g Sun)
Stellar Wind
+
Atmosphere
Evol. code
Geneva
evol. code
Observations
CMFGEN
code
Observations
Local
galaxies
distant
Universe
Young
stars
Pre-SN
Relation between evolutionary and spectroscopic phases
Groh+ 2014, A&A 564, 30
Predicting the look of massive stars across the cosmic time
Compared to “classical” stellar evolution criteria (based
on chemical abundances and Teff):
Longer LBV phase
Shorter WNL phase
WO stars at pre-SN
50% are in binaries, how does a binary evolve?
• RLOF removes stellar envelope
→hot core exposed
→(core can be ignited)
• A star grows in mass via accretion
→rejuvenation (hotter)
• Coalescence of a binary
→ a more massive star (hotter)
Binary interactions rejuvenate stars!
Zhanwen HAN
The Yunnan Model: EPS with Binaries
22
Binary
Contribution
to ISED
Han+ 2007, MNRAS, 380, 1098
Zhanwen HAN
The Yunnan Model: EPS with Binaries
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The Yunnan Model: with Binaries
 stellar evolutionary tracks
Yunnan
(Cambridge stellar evolution code STAR)
 BaSeL spectral library
 Binary interactions (blue stragglers, hot subdwarf stars,
rejuvenated stars, ……)
Binaries first included: Zhang+ 2004, A&A, 415, 117
Hot subdwarfs: Han+ 2007, MNRAS, 380, 1098
Blue stragglers: Chen+ 2009, MNRAS, 395, 1822
Accreting WDs: Chen+ 2015, MNRAS, in press
SFR calibration: Zhang+ 2012, MNRAS, 421, 743
Ionizing sources: Zhang+ 2015, MNRAS, 447, L21
Zhanwen
Zhanwen
HAN
HAN
The Yunnan
Model:
EPS
The Yunnan
Model: EPS
withwith
BinariesBinaries
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Stellar Physics in the Primitive Galaxy, I Zw 18
Sally Heap, J.C. Bouret, Ivan Hubeny
(NASA)
(LAM)
(U. AZ)
• FUV spectrum has very weak stellar spectral lines due to low Z~1/50-1/100 Z⊙
• Instantaneous starburst (age~5 ± 1Myr) in I Zw 18-NW
• Efficient rotation-induced mixing of nuclear products up to the stellar surface
• No stellar winds except in small minority population of BSS and/or CHE stars
• No galactic outflows
• Inhomogeneity in composition – evidence for Pop III stars
IAU GA August 2015 Hawaii
FM7: Stellar Physics in Galaxies
Ionizing Photon Production and Escape in Extreme Starbursts:
The Case of the Green Peas
A. E. Jaskot
Smith College
M. S. Oey
D. A. Carroll
University of Michigan University of Massachusetts
SDSS image
Flux (10-17 erg s-1 cm-2 Å-1)
[O III]
Hα
[O II]
Hβ
Wavelength (Å)
Ionizing Photon Production and Escape in Extreme Starbursts:
The Case of the Green Peas
WR stars needed
No WR features!
Padova models
Geneva models without rotation
Geneva models with rotation
5 Myr
3 Myr
Flux (10-17 erg s-1 cm-2 Å-1)
4 Myr
He II
Wavelength (Å)
Ionizing Photon Production and Escape in Extreme Starbursts:
The Case of the Green Peas
HST ACS
Emission Line
Mapping
HST COS
Spectra
Lyα
Si II
A complex approach to the blue-loop problem
Jakub Ostrowski
J. Daszyńska-Daszkiewicz
August 14, 2015, Honolulu
Introduction
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A long-standing problem of blue loops
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Almost 50 years of studies without a satisfying outcome
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The old codes and just a handful of models can’t
account for all complex interactions between different
parameters
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Our new approach: a modern code (MESA, Paxton et
al. 2011, 2013, 2015) and massive grid with many
varied parameters
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Main focus on massive stars
The results
✓
When rotation is included inward overshooting from the outer
convective zone is no longer necessary to produce a blue loop
✓
The μ-gradient profile is crucial for the emergence of the blue loops
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Blue loops are possible in more massive models (M > 13 M)
FM7 p.65 - Diagnostics of mixing processes
in atmospheres of low-mass stars
G. Tautvaišienė1, A. Drazdauskas1, S. Randich2,
R. Smiljanic3, Š. Mikolaitis1
1Vilnius University, Lithuania; 2INAF - Osservatorio Astrofisico di Arcetri, Italy;
3 Nicolaus Copernicus Astronomical Center, Poland
Thermohaline extra mixing:
Charbonnel & Lagarde, 2010, A&A, 522, A10
Lagarde et al., 2012, A&A, 543, A108
Boothroyd & Sackman 1999, ApJ, 510, 232
Red dots – this work, red circles (Tautvaišienė et al. 2000, 2005; Mikolaitis et al.
2010, 2011a,b, 2012), red triangles (Tautvaišienė et al. 2015); green circles
(Smiljanic et al. 2009), grey circles - Gilroy (1989), grey square - Luck (1994),
grey triangle - Santrich et al. (2013)
Observations show that theoretical models including a rotation-induced
mixing predict too low C/N ratios at all investigated turn-off masses, and too low
12C/13C ratios at large, about 4–7 M
Sun, turn-off masses.