space motion and stellar content of gcs with gems giuliana fiorentino university of bologna pi: a....

Space motion and Stellar content of GCs

with GeMS

Giuliana FiorentinoUniversity of Bologna

PI: A. McConnachie, CoI: P.B. Stetson, P. Turri, D. Anderson(NRC, Canada), G. Bono (University of Rome, Tor

Vergata), J.P. Veran (NRC, Canada)Date 26-06-2013, Florence

GeMS4ELT

MAD, a successful experiment

Date 09-07-2012, Leiden

2 arcmin

≤ R=13.5 mag

this limits the sky coverage

Pixel scale=0.028”/pixel

MAD in Nature:the case of Terzan 5

Date 09-07-2012, Leiden

d~ 6 KpcDate 09-07-2012, Leiden

Ter 5 host two different populations (confirmed by spectroscopic follow-up):

1)one old (12Gyr) and metal-poor trace the early stage of the bulge formation2)one young (6Gyr) and metal-rich could contain important information about the metal-enrichment and the dynamical evolution.

Terzan 5: a pristine fragment of the galactic bulge

[Fe/H]=-0.2 [Fe/H]=+0.3

Ferraro et al. (2009, Nature)

Deep and accurate CMDs are a feasible but not trivial target

We need to update software program that can account for a strong PSF variation when NGS do not allow a uniform correction . Normal packages do prefer to work with uniform correction even with low Strehl ratio. (updating for DAOPHOT, Stetson et al 1994, STARFINDER, Diolaiti et al. 2000).

Increase the sky coverage (e.g. laser guide stars, other ideas?).

Stability of the correction: reproducibility of the images to increase the S/N ratio.

Conclusions from MAD

Overtaking MAD:GSAOI/GeMS

★ GeMS pixel scale is 0.02”/pix --> comparable to MAD, 0.028”/pix. ★ GeMS FOV=83” --> comparable to MAD, camera=60”, FOV corrected 2x2’

★ GeMS (NGS, R≤15.5mag) has a larger SKY coverage than MAD (NGS, R≤13.5mag)

Date 26-06-2013, Florence

GeMS4ELT

NGC1851d~12Kpc

E(B-V)~0.02

~

The Project: Globular Clusters

★ PROPER MOTIONS

★ STELLAR POPULATIONS

★ GeMS characterization and comparison with MAD@VLT


GeMS4ELT

GeMS4ELT


Proper Motions

★ Foreground cleaning using Proper Motions of field and cluster stars.

★ Systemic Proper motions: measurements of the tangential velocity (~10 km/sec for distances ≤10 Kpc) PM~0.0002”/year over 5-10 years PM=1-2 mas ~ the accuracy on each star -> σ PM/√N thousand of stars per GGC. possibility to trace GGCs in space and in time (using cluster ages) providing a link to their birthplace, thus constraints on the formation scenario of the Galaxy.

★ Internal Proper Motions: measure of the radial velocity dispersion profile and/or detection of high velocity stars very close to the center (as in our Galactic Center).

with high accuracy (σ PM~1-2 mas) we could obtain constraints on the occurrence of IMBH (M~104Mo) in the center of Globular Clusters.

HST (1st epoch) -- GeMS (2nd epoch?)

1) “ad hoc” for NIR-filters

2)Based on a different physics: in low mass star (≤0.4Mo), due to collision-induced absorption of hydrogen moleculesJ-K (mag)

K (

mag

)

NIR CMD of NGC3201 as provided by the combination of MAD (red dots) and SOFI (black dots). The blue and purple points highlight the Main Sequence Turn Off (MSTO) and the Main Sequence Knee (MSK) locations.

NGC3201 MAD+SOFI data

GeMS4ELT


NGC3201 as seen by MAD

Stellar Populations and ages

classical MSTO

new MSK

NGC3201d~5Kpc

E(B-V)~0.25-0.30

Independent of Reddening,differential-Reddening and Distance

σ(MSK)~σ(MSTO)/2

Bono et al. 2010, ApJL

The First Targets


GeMS4ELT

ID D(Kpc)[Fe/H] E(B-V) σv(km/s) CC AGE(Gyr) ABS_PMs(mas/year)

NGC1851 12.1 -1.18 0.02 10.4±0.5 N 10.0 1.28±0.68 2.39±0.65 NGC5904(M5) 7.5 -1.29 0.03 5.5±0.4 N 10.6 5.20±1.70 14.20±1.30 NGC6652 10.0 -0.81 0.09 n.d. N 12.9 n.d. NGC6681(M70) 9.0 -1.62 0.07 5.2±0.5 Y 12.8 n.d.NGC6723 8.7 -1.10 0.05 n.d. Y 13.1 n.d.NGC7078(M15) 10.4 -2.37 0.10 13.5±0.9 Y 12.9 2.40±1.00 8.30±1.00

Large Metallicity range

d≤12Kpc Low reddening

Velocity Dispersion σv ≤ 13 km/s

core collapse Systemic Proper motions≤15mas/year

with errors ≤ 1mas/year

They all have exquisite HST (WFPC2-ACS) photometry

(a) GeMS/GSAOI Ks image of NGC1851 (one of the four arrays) showing the high quality data obtained during the Science Verification; (b) Magnification of the region highlighted in red; (c) Same region as seen by HST/ACS in F814W filter (Sarajedini et al. 2007). The GSAOI Ks data has a very similar FWHM to the HST optical data and is very uniform across the entire field.

GeMS

ACS@HST

GeMS4ELT


FIRST GSAOI/GeMS resultsNGC1851 effective pixel scale = 0.03”/pixel

DL(V)=0.05”V-band

DL(K)=0.07”K-band

GeMS4ELT


VERY PRELIMINARY CMD

VERY PRELIMINARY: DAOPHOT/ALLSTAR/ALLFRAME for 1 chip (P. Turri, PhD Thesis)

ISOCHRONES from Dotter et al. 2007 WEBsite Z=0.001 age=10Gyrs

GeMS4ELT


ACS@HST + GeMS


83”

202”

202”

83”

V~25 mag


chip 1 chip 2

chip 3

chip 4

GeMS4ELT


ACS@HST + GeMS


Ks~22 mag


GeMS4ELT


Luminosity Functions

Texp=1920s S/N~7 K~ 22.5 mag

Texp= 2720s S/N~10 J~ 22.5 mag


GeMS4ELT


FWHM mapsJ-band DL(J)~0.05”Ks-band DL(Ks)~0.07”

14

12

1212

14

12

seeing~0.7-0.8” seeing~1.0”

GeMS4ELT


SR mapsJ-band <SR>~10%K-band <SR>~27%

40

35

30

25

20

15

10

5

0

12

14

12 12

14

12

seeing~0.7-0.8” seeing~1.0”

GeMS4ELT


GeMS has obtaining very interesting performances!!

If the photometric (Ks~22.5 mag with S/N~7) and astrometric (≤1 mas/year) accuracies

are exactly what we guess:

in the near future you will read a lot about GeMS!!

Conclusions

Looking for the near and next future....THANKS!

Metropolitan Museum of art, NY city


space motion and stellar content of gcs with gems giuliana fiorentino university of bologna pi: a....

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