Transcript The Fate of the X-ray Emitting Gas in the Early

The Fate of the X-Ray Emitting Gas in the
Early-Type Galaxy NGC 5044
X-Ray Brightest Group in the Sky
Jeremy Lim
William Forman
Jan Vrtilek
Christine Jones
Ewan O’Sullivan
Francoise Combes
Philippe Salome
Simona Giacintucci
Alastair Edge
Ming Sun
O’Sullivan
Stephen Hamer
Pasquale Temi
Henrique Schmitt
Youichi Ohyama
William Mathews
Fabrizio Brighenti
Dinh-V Trung
Highly Perturbed X-Ray Morphology
Raw 0.5-2.0 keV Chandra ACIS images
 Many small cavities inflated by repeated
AGN outbursts that essentially blow in
the wind.
 Sloshing induced cold fronts.
 Pcav= 6.5 x 1043 erg s-1 ~ Lx within the
central 25 kpc.
 tcool= 4 x 107 yr
 Mass deposition rate = 5 M yr-1
νLν (erg s-1)
Radio Properties of the Central AGN
 Many weak AGN outbursts
GMRT data at 235 MHz
 Pcav for smallest X-ray cavity is 3 x
1041 erg s-1
 νLν (230GHz) = 500 νLν (630MHz).
 tage = 5 Myr assuming equipartion and
a break frequency of 230 GHz.
CO(2-1) ALMA Observations
 24 molecular structures
detected above 4σ within the
central 2.5 kpc.
 Mmol = 3 x 105 – 107 M
 Mmol (tot) = 5 x 107 M
 σv = 15 – 65 km s-1
 Linewidths are too broad to
be GMCs and are likely
Giant Molecular Associations
(GMAs).
 The GMC filling factor in the
few resolved GMAs is 15%.
Comparison of IRAM 30m and ALMA Data at CO(2-1)
IRAM 30m
ALMA
 Good agreement between
ALMA and IRAM 30m for
redshifted CO emission.
 The blueshifted IRAM flux is 5
times greater than the
blueshifted ALMA flux.
 This implies that there is a
significant amount of large
scale (R>300 pc) blueshifted
diffuse CO emission that is
resolved-out in the ALMA
data.
High Resolution Spectrum of Most Massive
Molecular Structure
 GMA 18 is well fit with a
double Gaussian (σv= 5.5
and 37.5 km s-1).
 Mmol=1.0 x 107 M
 rc=140 pc
 α=5σv2rc/GMmol=24
 GMA 18 is not gravitationally
bound.
 GMA 18 is not pressure
confined (Pturb > Phot).
 GMA 18 will dissipate on a
timescale t=2rc/σv=10 Myr.
 The linewidth of the narrow
line feature is typical of an
individual virialized GMC.
CO(2-1) Position-Velocity Diagram

 GMAs 13 and 18 are distinct molecular
structures
 No apparent disk-like structures near
the central AGN.
 P-V diagram consistent with infall
Kinematics of the Molecular Gas
 GMAs 11 and 13 have velocities near the
systemic velocity of NGC 5044 far from
the AGN and increasing blueshifted
velocities near the AGN.
 This suggests that these GMAs are falling
into the AGN from the far side of the
galaxy.
 The velocity gradient of GMA 18 is
perpendicular to that expected for a disk
rotating about the AGN.
CO(2-1) Absorption Feature
in the AGN Continuum
 Fitting a Gaussian profile to the
absorption feature gives:
<v>=260 km s-1 and σv = 5.2 km
s-1. For comparison, the circular
velocity is 325 km s-1.
 The linewidth is typical of an
individual GMC.
 Optical depth at line-center is
τ=0.35.
 Either 30% of the 230 GHz
emission region is covered by an
optically thick cloud or the entire
230 GHz emission region is
covered by an optically thin
cloud.
 Assuming the absorption feature
is due to a GMC and using a
standard linewidth-size relation
implies that the 230 GHz
emission region is smaller than
50 pc in radius.
Correlations Between the Molecular Gas and Dust
and Ha Filaments
 A few of the GMAs are obviously
correlated with dust.
 A few of GMAs trace the dust filament to
the NW.
 Many GMAs are not associated with dust
or Ha emission.
Summary of ALMA Results
Source of cold gas:
 Velocity dispersion of the GMAs is 122 km s-1, which is less than the stellar
velocity dispersion of 237 km s-1.
 Several GMAs are likely on infalling, nearly radial orbits
 No disk-like structures
 GMAs have a nearly azimuthially symmetric distribution
 Mass deposition rate is 25 times greater than the stellar mass loss rate.
 The molecular gas arises from the thermally unstable hot gas.
 Supply time is greater than 10 Myr and could be as much as 100 Myr.
Dynamics:
 For buoyancy to be important the AGN inflated cavities much displace a
mass equal to the molecular mass. The displaced mass in the X-ray
cavities is only 15% of the molecular mass.
 There are no large scale radio jets in NGC 5044.
 Molecular structures likely follow ballistic orbits after condensing out of the
hot gas.
 The GMAs are not gravitationally bound or pressure confined and should
disperse on a timescale of approximately 10 Myr.
Summary of ALMA Results
Star Formation:
 The observed star formation rate is 0.073 M yr-1 (Werner et al. 2014).
 Based on the Kennicutt-Schmidt relation, the total star formation rate from
the three best resolved GMAs is 0.03 M yr-1 .
 Since these three GMAs comprise 35% of the total molecular mass, there is
reasonable good agreement with the observed star formation rate.
 The depletion time of the molecular gas due to star formation is 700 Myr.
 Assuming one SNeII for each 100 M of gas consumed into stars, implies
that SNeII will produce an energy equivalent to 60% of the total turbulent
kinetic energy in GMA 18 over its lifetime.