PRISTINE: ESPADONS Pristine Footprint 2015A · Pristine Footprint 2015A Pristine 15A with CFHT/MegaCam Belokurov et al. (2007) PRISTINE: ESPADONS This talk: Kim Venn (U.Victoria,
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Pristine Footprint 2015A
Pristine 15Awith CFHT/MegaCam
Belokurov et al. (2007)
PRISTINE: ESPADONS
This talk: Kim Venn (U.Victoria, Canada)
Pristine Team: co-leads Nicolas Martin & Else Starkenburg
Team Members: Rodrigo Ibata, Vanessa Hill, Pascale Jablonka, Piercarlo Bonifacio, Elisabetta Caffau, Patrick Francois, Ruben Sanchez-Janssen, Ray Carlberg, Julio Navarro, Alan McConnachie, Pat Cote, Steve Gwyn, Kris Youakim, Collin Keilty, and more.
Alan McConnachie, Pat Cote
Follow up spectra for V<14.7 with Espadons* Targeting metal-poor stars with [Fe/H] < -2, with initial analysis of red giants with T<6000 K.
38 Espadons targets observed in 2016A 21 with predicted [Fe/H] < -2.5 (>80% confidence)
Examination of key features: 13 showed weak & narrow CaT, MgB, & Balmer (62%)
SNR>20 pipeline spectra
No RV corr.s
No rebinning
850 855 860 865-3
-2
-1
0
1
Wavelength
P7
P27
P56
P45
P30
P6
P1
3 (of 13) new
metal-poor [Fe]< -2.5
bright stars
512 514 516 518 520-3
-2
-1
0
1
Wavelength
P7
P27
P56
P45
P30
P6
P1
3 (of 13) new
metal-poor [Fe]< -2.5
bright stars
SNR>20 pipeline spectra
No RV corr.s
No rebinning
8 (of 13) Espadons targets observed in 2016A
with predicted [Fe/H] < -2.5 with weak & narrow CaT, MgB, & Balmer coadded & smoothed for SNR > 30
5150 5160 5170 5180 5190-3
-2
-1
0
1
Wavelength
P27s
P43s
P7s
P56s
PP4
PP6s
P62s
P240s
8 (of 13) Espadons targets observed in 2016A
with predicted [Fe/H] < -2.5 with weak & narrow CaT, MgB, & Balmer coadded & smoothed for SNR > 65
Standard MOOG analysis preference for cooler stars - grid atmospheres, OSMARCS (Plez et al.) - shortened line list, (can squeeze out more) - LTE
example P7
8 (of 13) Espadons targets observed in 2016A
with predicted [Fe/H] < -2.5 with weak & narrow CaT, MgB, & Balmer coadded & smoothed for SNR > 65
Standard MOOG analysis preference for cooler stars - grid atmospheres, OSMARCS (Plez et al.) - shortened line list, (can squeeze out more) - LTE
Microturbulence? - few lines, small range can make determination difficult. - not clear if standard gravity- vturb relations apply. - can have significant effect on metallicities and ratios.
example PP6
8 (of 13) Espadons targets observed in 2016A
with predicted [Fe/H] < -2.5 with weak & narrow CaT, MgB, & Balmer coadded & smoothed for SNR > 65
Temperatures up to 400 K cooler than predicted from Pristine colour calibrations.
[Fe/H] tends to be similar, though Espadons ~lower and INT FERRE ~higher.
5000 5500 6000 6500
5000
5500
6000
6500
T(Pristine colours)
-3.5 -3 -2.5 -2
-3.5
-3
-2.5
-2
PRISTINE
SCULPTOR dSph: Jablonka et al. 2015, Hill et al. 2010, Tafelmeyer et al. 2010, Frebel et al. 2010, Letarte et al. 2010, Shetrone et al. 2003
CARINA dSph: Venn et al. 2012, Lemasle et al. 2012, Koch et al. 2008 Shetrone et al. 2003
UFD: Ishigaki et al. 2014, Frebel et al. 2014, 2010 Simon et al. 2014, Aden et al. 2011, Norris et al. 2010, Koch et al. 2010,
MWG: Aoki et al. 2013, Yong et al. 2013, Reddy et al. 2010, 2008, Frebel et al. 2010, Venn et al. 2004
Nes
s et
al.
2013
K
elle
r et a
l. 20
14
Some chemical evolution models support inhomogeneous mixing and thereby thatsome First Stars have high metallicities.
Wise et al. 2012
One goal of Pristine is to find more metal-poor stars, especially interesting metal-poor stars.
PRISTINE SCULPTOR dSph CARINA dSph UFD MWG
Limits Ba II 4554 1 mA 3 mA 10 mA
Low [Ba/Fe] in Segue I extremely interesting ... because high [Fe/H] from a single SN event in a low mass system, that did not produce much r-process.
Rare objects. First stars?
Frebel et al (2014)
Copious r-process enrichment from a single event in Ret II Ji et al. 2016 Nature
“Universal r-process pattern”, yet “incompatable with ordinary core collapse SN yields, but consistent with r-process production in neutron star mergers”.
Summary
1. Pristine-MegaCam survey with CaH&K filters appears to be excellent at finding metal-poor stars.
2. Pristine-Espadons has excellent spectral quality (resolution and SNR V<14.7) for follow-up studies.
3. ~60% of Pristine predicted [Fe/H] < -2.5 stars confirmed with spectroscopy (13/21 so far).
4. Analysis of 8/13 shows normal metal-poor halo stars, but these are bright objects that are idea for very detailed follow-up (e.g., r-process patterns).
PRISTINE objects are normal halo stars, none with low [Sr/Fe] often seen in dwarf galaxies, possibly due to metallicity-dependent nucleosynthetic yields.
CARFNXSCLSEXTDRALEOIVCOMUMAIIBOO
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