the muse view on the dynamics of gcs - cosmic-lab · intermediate-mass black holes stellar...

The MUSE view on the dynamics of GCs

Sebastian Kamann (IAG)T.-O. Husser, B. Giesers, S. Dreizler (IAG),D. Krajnović, M. M. Roth, P. Weilbacher, M. Wendt, L. Wisotzki (Potsdam), E. Emsellem (ESO), J. Brinchmann (Leiden), R. Bacon (Lyon)

22016/04/21MODEST 2016 - Sebastian Kamann (IAG)

Why integral-field spectroscopy?

“traditional” spectroscopyneeds isolated starsfew targets in centre of GConly brightest giants

centre of M13 (seeing ~0.7”)


Why integral-field spectroscopy?

“traditional” spectroscopyneeds isolated starsfew targets in centre of GConly brightest giants

integral-field spectroscopyspatial information preservedanalysis similar to imagesdeblend sources

centre of M13 (seeing ~0.7”)


PampelMuse

PSF-based extraction for integral-field data (Kamann+13)example for NGC 6397:


An example: Looking for an IMBH in M92

seeing-limited IFU observations with PMAS~80 stellar spectra extracted

central dispersion from individual velocities: MBH < 10³ Msun

HST PMAS

Kamann+14



uncovering the integrated lightresolved stars along red giant branchknow positions & PSF

HST PMAS



uncovering the integrated lightresolved stars along red giant branchknow positions & PSF → subtract them

HST PMAS



uncovering the integrated lightresolved stars along red giant branchknow positions & PSF → subtract them

use resolved & unresolved stars : MBH < 7x10² Msun

HST PMAS


MUSE in a nutshell

commissioned 2014 at the VLT

panoramic IFScombination of 24 IFUs1'x1' FoV with 0.2” samplingλ ~ 4800Å – 9300Å

R ~ 1770 – 3590

“point and shoot”very stablehigh throughputexcellent optical quality


Why MUSE?

>2 nights of PMAS: <5 hours of MUSE:


A large MUSE survey

ongoing observations of ~25 clusters with MUSE

aim: ~10000 stars per cluster, multi-epoch observations

science cases:binary fractions and periodsintermediate-mass black holesstellar parameter analysesserendipitous discoveries

currently: ~1000 exposures 30 TB of data

NGC 6441


Legacy value of blind spectroscopy

example: Planetary nebula in NGC 6441


Our testbed: NGC 6397

nearby GCmoderate masscentral dispersion ~5 km/s[Fe/H] = -2


Our testbed: NGC 6397

nearby GCmoderate masscentral dispersion ~5 km/s[Fe/H] = -2

19000 spectra / 12000 stars(could be even more ...)10500 spectra with S/N>10(almost) complete CMD

And

erso

n et

al.

(200

8)


Velocity dispersion profile of NGC 6397

remember: σ~5 km/s challenging for kinematics!

at large radi:good agreement between MUSE and HR studies

at small radii:MUSE can probe much closer to the centre


Velocity dispersion profile of NGC 6397

remember: σ~5 km/s challenging for kinematics!

at large radi:good agreement between MUSE and HR studies

at small radii:MUSE can probe much closer to the centre

kinematics as function of stellar mass


Possibility for 2D kinematics

Rotation Dispersion


Jeans models for NGC 6397

IMBH central excess of remnants

isotropic models using JAM code (Cappellari+08)central dispersion underestimated with constant M/Lexcess mass of 600 Msun

two explanations:


The other clusters

analysis of full sample currently in progresssome impressions:

NGC 3201


The other clusters


NGC 3201NGC 7089


The other clusters


NGC 3201NGC 7089NGC 2808

282016/03/22Massive multiplex MUSE spectroscopy in globular clusters S. Kamann (IAG)

Searching for binaries with MUSE

dedicated multi-epoch strategysearch for RV Variables

complementary to photometryBSSs, neutron stars, ...

example: NGC 3201~3200 stars with S/N > 105 epochs of data

analysis: Benjamin Giesers


The binary fraction in NGC 3201

very consistent results from all epochs:

ultimate goal is to get binary periodsstill more epochs needed

(9.1 ± 1.4) %


The binary fraction in NGC 3201

very consistent results from all epochs:

ultimate goal is to get binary periodsstill more epochs needed

(9.1 ± 1.4) %

Δt [days]

v_ra

d [k

m/ s

]


Blind spectroscopy: BSSs in M30

Ferraro et al. (2010) MUSE RV variability


Conclusions

Crowded field 3D spectroscopy is a powerful tool to investigate globular cluster dynamics.

MUSE is great!spectroscopy with unprecedented sample sizes blind spectroscopy → wide unexplored spaceMUSE+AO is coming soon

the muse view on the dynamics of gcs - cosmic-lab · intermediate-mass black holes stellar...

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