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An update on SMBHs in UCDs Steffen Mieske ESO Chile MODEST 17 meeting Prague Sept. 18-22, 2017 Seth Voggel Chilingarian Afanasyev Neumayer Baumgardt Lützgendorf Hilker Frank
An update on SMBHs in UCDs Steffen Mieske
ESO Chile
MODEST 17 meeting Prague
Sept. 18-22, 2017
Seth Voggel Chilingarian Afanasyev
Neumayer Baumgardt Lützgendorf
Hilker Frank
Hilker
UCD
Normal dwarf UCDs
Misgeld & Hilker 2011
UCD UCDs are believed to be
Massive star clusters (e.g. Fellhauer & Kroupa 2002,2005, Mieske+ 2002)
and/or Tidally threshed galaxies
(Bekki et al. 2003, Drinkwater et al. 2003, Pfeffer & Baumgardt 2013)
UCD
Normal dwarf
Michael Hilker
Measure global velocity dispersion
Dynamical modelling
using HST surface brightness
profiles
Include slit effects
Seeing limited spectroscopic observation
Elevated dynamical M/L of UCDs
UCDs
GCs
No dark mass
Dark mass
Literature: McLaughlin et al. 2005, Hasegan et al. 2005, Evstigneeva et al. 2007, Hilker et al. 2007, Mieske et al. 2008 & 2013, Chilingarian & Mamon 2008, Taylor et al. 2010, Chilingarian et al. 2011
Mieske et al. 2013
Dark mass
No dark mass
Normal dwarf UCDs
Misgeld & Hilker 2011
Mieske et al. (2013): calculate central BH masses in UCDs needed to elevate M/L (Mieske, Frank, Baumgardt, Luetzgendorf, Neumayer, Hilker, A&A 2013, 558, 14)
Typical inferred BH mass fraction is 10% of UCD mass
UCDs
Prediction: Massive UCDs should have ~10% relative BH masses
Luetzgendorf+ 2013
McConnell & Ma 2013
Mieske+ 2013
UCDs
Prediction: Massive UCDs should have ~10% relative BH masses
Massive BHs in UCDs would thus be relics of massive UCD progenitors. (Bekki et al. 2003, Pfeffer & Baumgardt 2013)
Mieske+ 2013
UCDs
Luetzgendorf+ 2013
McConnell & Ma 2013
To resolve the kinematical signature of an SMBH in UCDs,
one needs AO assisted spectroscopy
Joint Gemini North & VLT campaign to resolve UCD dynamics [PIs Seth, Mieske]
M60 UCD1
1”/80 pc!
M60!
NGC 4647!
M60-UCD1!
M60 UCD
Velocity Dispersion
Data
Model
Resolving the BH sphere of influence in M60-UCD1 (Seth et al. Nature 2014)
M60 UCD
Best fit Schwarzschild model
M_BH = 2.1 * 107 M*
Case of no BH rejected at 4σà A supermassive black hole
with 15% of the UCD mass
Resolving the BH sphere of influence in M60-UCD1 (Seth et al. Nature 2014)
• Jeans models consistent with Schwarzschild models and isotropy
M60 UCD black hole in context
M60 UCD
Offset from the L-BH relation suggests significant tidal stripping Progenitor Bulge of ~1010 M*
What is the occupation fraction of SMBHs in UCDs?
Gemini+VLT campaign 2015+2016 (PIs Seth, Mieske) Goal: constrain central BH masses in 11 nearby UCDs (<20 Mpc) à Do SMBHs in UCDs contribute
significantly to the local SMBH density?
à Which fraction of UCDs originates from galaxies?
What is the occupation fraction of SMBHs in UCDs?
Gemini+VLT campaign 2015+2016 (PIs Seth, Mieske) Goal: constrain central BH masses in 11 nearby UCDs (<20 Mpc) à Do SMBHs in UCDs contribute
significantly to the local SMBH density?
à Which fraction of UCDs originates from galaxies?
New UCD BH results, 1 SINFONI+LGS of CenA UCDs
Voggel et al. (2017, in prep): No strong kinematical indication for SMBH in CenA UCDs
CenA UCD 330 (HST archival) CenA UCD 320 (ACS, courtesy A. Romanowsky)
New UCD BH results, 2
Ahn et al. (2017): SMBHs confirmed in two Virgo UCDs
Gemini-N NIFS
MBH= 4.4+-0.9 * 106M*
MBH= 5.8 +-0.9 * 106M*
New UCD BH results, 3 SINFONI+LGS of Fornax UCD 3
New UCD BH results, 3 SINFONI+LGS of Fornax UCD 3
PRELIMINARY radial velocity dispersion profile: - New SINFONI data, PSF is combination of 0.15” core and 1.0” wing - Seeing limited FLAMES data from Frank et al. (2011), PSF ~0.55”
Afanasyev et al. 2017, in preparation
New UCD BH results, 3 SINFONI +LGS of Fornax UCD 3
PRELIMINARY radial velocity dispersion profile: - New SINFONI data, PSF is combination of 0.15” core and 1.0” wing - Seeing limited FLAMES data from Frank et al. (2011), PSF ~0.55”
Mass of SMBH = 4 +2-1.5 *106 M*
(~5% of UCD mass)
Afanasyev et al. 2017, in preparation: SMBH detected at 98% confidence
What is the occupation fraction of SMBHs in UCDs: Update Q3/2017
SMBH occupation fraction: 4 out of 6 100% for UCD mass ~10^8 0% for UCD mass ~10^7
What is the occupation fraction of SMBHs in UCDs: Update Q3/2017
SMBH occupation fraction: 4 out of 6 100% for UCD mass ~10^8 0% for UCD mass ~10^7
Pfeffer et al. (2016) Number of stripped nuclei expected from simulations vs. number of observed CSSs
Summary 1. UCDs (compact stellar systems more massive than ωCen) are a
mixed bag of objects consisting of massive star clusters and tidally stripped dwarf galaxies. 2. Elevated dynamical M/L ratios of massive UCDs suggest dark mass
3. SMBH occupation fraction of UCDs supports a scenario where:
• UCDs with masses >107.5 M* mostly are tidally stripped galaxies
• UCDs with masses <107 M* mostly are massive star clusters This is consistent with theoretical studies on the number ratio between tidally threshed naked nuclei and star clusters as f(m)
Outlook
• Complete ongoing SMBH survey in UCDs • And start going after UCD progenitors
• Investigate alternative explanations for
elevated dynamical M/L of UCDs • e.g. global IMF variation or central dark
remnants • bad measurements....
• Stellar population and kinematical trends
among large samples of GCs & UCDs
Outlook
?
Pechetti et al. (2017, almost accepted): Constraining SMBH masses in low mass ETGs (UCD progenitors)
based on ATLAS 3D
Announcement of opportunity at the VLT: MUSE-AO in narrow field mode to come soon
7“x7“ IFU in the optical with high perfomance AO (0.03“- 0.05“ resolution) Science verification planned for mid 2018
Announcement of opportunity at the VLT: MUSE-AO in narrow field mode to come soon
7“x7“ IFU in the optical with high perfomance AO (0.03“- 0.05“ resolution) Science verification planned for mid 2018
Announcement of opportunity at ESO: ESO fellowships Garching & Chile Deadline October 15
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