A 3-‐D view of the galaxy-‐wide shock in Stephan`s Quintet

A 3-‐D view of the galaxy-‐wide shock in Stephan`s Quintet

A 3-­‐D view of the galaxy-­‐wide shock in Stephan’s Quintet
Jorge Iglesias-­‐Páramo
InsCtuto de AstroDsica de Andalucía (CSIC)
Luis López (IAC)
José M. Vílchez (IAA)
Vasiliki Petropoulou (IAA)
Jack SulenCc (IAA)
Properties of Stephan’s Quintet
Stephan (1877)
Properties of Stephan’s Quintet
3 galaxies with accordant radial velocities
Stephan (1877)
Properties of Stephan’s Quintet
3 galaxies with accordant radial velocities
1 foreground galaxy
Stephan (1877)
Properties of Stephan’s Quintet
3 galaxies with accordant radial velocities
1 new intruder galaxy
Stephan (1877)
1 foreground galaxy
Properties of Stephan’s Quintet
3 galaxies with accordant radial velocities
1 old intruder galaxy
1 new intruder galaxy
Stephan (1877)
1 foreground galaxy
Properties of Stephan’s Quintet
3 galaxies with accordant radial velocities
1 old intruder galaxy
1 new intruder galaxy
Stephan (1877)
2 stellar tails (relics of interactions)
1 foreground galaxy
Properties of Stephan’s Quintet
3 galaxies with accordant radial velocities
1 old intruder galaxy
1 new intruder galaxy
Stephan (1877)
2 perturbed arms
2 stellar tails (relics of interactions)
1 foreground galaxy
Properties of Stephan’s Quintet
3 galaxies with accordant radial velocities
2 perturbed arms
1 old intruder galaxy
2 stellar tails (relics of interactions)
1 new intruder galaxy
2 starbursts
Stephan (1877)
1 foreground galaxy
Properties of Stephan’s Quintet
Extended X-ray and radio-continuum emissions indicate the existence of a shock
(Pietsch et al. 1997, Sulentic et al. 2001, Xu et al. 2003, Trinchieri et al. 2005).
Radio 20cm
ROSAT HRI
ROSAT HRI
l 
Properties of Stephan’s Quintet
Also observed at UV (GALEX), and IR (Spitzer) wavelengths
Guillard et al. (2010)
Properties of Stephan’s Quintet
Also observed at IR (Spitzer) wavelengths: molecular emission without signatures
of star formation (Appleton et al. 2006, Guillard et al. 2010, 2012).
Guillard et al. (2010)
Properties of Stephan’s Quintet
Previous optical emission line studies of the ionized gas in the shock region
[OII]
Hβ
[OIII]
[OI] Hα +[NII] [SII]
Xu et al. (2003)
Properties of Stephan’s Quintet
Previous optical emission line studies of the ionized gas in the shock region
Oyhama et al. (1998)
Properties of Stephan’s Quintet
Mid-IR H2 emission shows no spectroscopic signatures of star formation
(Guillard et al. 2009)
The pre-shock gas shows a multiphase structure.
Observations
Observations with PMAS @ T3.5m CAHA
16 x 16 square elements (binned to 8 x 8 for the
analysis)
1.0” sampling, 16” x 16” FOV
R600 grating with R.A. 143.3º: [3810,5394]Å
R.A. 146.1º: [5305,6809]Å
Spectral resolution: ~3.6Å
Observations
Three pointings along the shock.
6.88kpc
Results
A 2x2 binning is performed for the analysis (results in 64 spectra
per pointing and better signal-to-noise)
Results
A 2x2 binning is performed for the analysis (results in 64 spectra
per pointing and better signal-to-noise)
Results
A 2x2 binning is performed for the analysis (results in 64 spectra
per pointing and better signal-to-noise)
Results
A 2x2 binning is performed for the analysis (results in 64 spectra
per pointing and better signal-to-noise)
Results
Emission dominated by
2 bright HII regions
6650Å < λ < 6750Å
Results
Emission dominated by:
1 HII region
&
diffuse complex emission
6650Å < λ < 6750Å
Results
Emission dominated by
complex emission.
6650Å < λ < 6750Å
Results
Line fitting: with MPEXPFIT.
Complex kinematical structure: several blended components.
But, how many?
Results
Line fitting: with MPEXPFIT.
Complex kinematical structure: several blended components.
How many?
Results
Line fitting: with MPEXPFIT.
Complex kinematical structure: several blended components.
How many?
Results
Results
Results
Results
Emission dominated by
2 bright HII regions
6650Å < λ < 6750Å
Results
1 component
HII-like spectrum
v = 5670.9 km/s
σ = 38.7 km/s
[OIII]λ5007Å/Hβ = 1.94
[NII]λ6583Å/Hα = 0.3
Results
Emission dominated by:
1 HII region
&
diffuse complex emission
6650Å < λ < 6750Å
Results
2 components
Low-velocity comp.
v = 5918.1 km/s
σ = 109.5 km/s
[OIII]λ5007Å/Hβ = --[NII]λ6583Å/Hα = 0.94
 
High-velocity comp.
v = 6349.8 km/s
σ = 196.0 km/s
[OIII]λ5007Å/Hβ = --[NII]λ6583Å/Hα = 0.24
 
Results
Emission dominated by
complex emission.
6650Å < λ < 6750Å
Results
2 components
Low-velocity comp.
v = 6126.9 km/s
σ = 196.0 km/s
[OIII]λ5007Å/Hβ = --[NII]λ6583Å/Hα = 0.62
 
High-velocity comp.
v = 6770.4 km/s
σ = 196.0 km/s
[OIII]λ5007Å/Hβ = --[NII]λ6583Å/Hα = 0.05
 
Results
Low-velocity comp., f(Hα)
0.1
6.7
13.4
10-16 erg s-1 cm-2
Low-velocity comp., vrad
20
5500
5875
6250
km s-1
6625
7000
Results
High-velocity comp., f(Hα)
0.1
6.7
13.4
10-16 erg s-1 cm-2
High-velocity comp., vrad
20
5500
5875
6250
km s-1
6625
7000
Results
Pointing S
Results
Pointing S
Most spectra consistent with a single component with
recession velocity similar to that of NGC7318b (new
intruder).
Results
Pointing S
Most spectra consistent with a single component with
recession velocity similar to that of NGC7318b (new
intruder).
Bright spaxels show velocity dispersion consistent
with star forming regions.
Results
Pointing S
Most spectra consistent with a single component with
recession velocity similar to that of NGC7318b (new
intruder).
Bright spaxels show velocity dispersion consistent
with star forming regions.
[NII]6583/Hα ≤ 0.4 for the bright spaxels.
SF models (Dopita et al.)
Shock models (Allen et al.)
Low velocity
High velocity
Results
Pointing S
Most spectra consistent with a single component with
recession velocity similar to that of NGC7318b (new
intruder).
Bright spaxels show velocity dispersion consistent
with star forming regions.
[NII]6583/Hα ≤ 0.4 for the bright spaxels.
SF models (Dopita et al.)
Shock models (Allen et al.)
Low velocity
High velocity
Results
Pointing M
Results
Pointing M
Most spectra consistent with two components with
velocities 5800<v<6300km/s (increasing towards the
North-West) and ~6700km/s.
Results
Pointing M
Most spectra consistent with two components with
velocities 5800<v<6300km/s (increasing towards the
North-West) and ~6700km/s.
Low velocity dispersion of the bright spaxel (~25km/
s) and >50km/s for the rest.
Results
Pointing M
Most spectra consistent with two components with
velocities 5800<v<6300km/s (increasing towards the
North-West) and ~6700km/s.
Low velocity dispersion of the bright spaxel (~25km/
s) and >50km/s for the rest.
[NII]6583/Hα low (high) for the high- (low-) velocity
component.
Results
Pointing M
Most spectra consistent with two components with
velocities 5800<v<6300km/s (increasing towards the
North-West) and ~6700km/s.
Low velocity dispersion of the bright spaxel (~25km/
s) and >50km/s for the rest.
[NII]6583/Hα low (high) for the high- (low-) velocity
component.
SF models (Dopita et al.)
Shock models (Allen et al.)
Low velocity
High velocity
Results
Pointing M
Most spectra consistent with two components with
velocities 5800<v<6300km/s (increasing towards the
North-West) and ~6700km/s.
Low velocity dispersion of the bright spaxel (~25km/
s) and >50km/s for the rest.
[NII]6583/Hα low (high) for the high- (low-) velocity
component.
SF models (Dopita et al.)
Shock models (Allen et al.)
Low velocity
High velocity
Results
Pointing N
Results
Pointing N
Most spectra consistent with two components with
velocities at ~6100km/s and ~6700km/s. Low signalto-noise towards the West.
Results
Pointing N
Most spectra consistent with two components with
velocities at ~6100km/s and ~6700km/s. Low signalto-noise towards the West.
High velocity dispersion (>100km/s) for most spaxels
in both components.
Results
Pointing N
Most spectra consistent with two components with
velocities at ~6100km/s and ~6700km/s. Low signalto-noise towards the West.
High velocity dispersion (>100km/s) for most spaxels
in both components.
[NII]6583/Hα low (high) for the high- (low-) velocity
component.
Results
Pointing N
Most spectra consistent with two components with
velocities at ~6100km/s and ~6700km/s. Low signalto-noise towards the West.
High velocity dispersion (>100km/s) for most spaxels
in both components.
[NII]6583/Hα low (high) for the high- (low-) velocity
component.
SF models (Dopita et al.)
Shock models (Allen et al.)
Low velocity
High velocity
Results
Pointing N
Most spectra consistent with two components with
velocities at ~6100km/s and ~6700km/s. Low signalto-noise towards the West.
High velocity dispersion (>100km/s) for most spaxels
in both components.
[NII]6583/Hα low (high) for the high- (low-) velocity
component.
SF models (Dopita et al.)
Shock models (Allen et al.)
Low velocity
High velocity
Results
The ionized components could be the links between the disconnected HI filaments
reported in Williams et al. (2002).
Results
Hwang et al. (2012)
Is this result consistent with the expected metallicities of the HI filaments?
Results
The oxygen abundances derived for individual HII regions (in this work and in the literature)
suggest that this could be the case.
Hwang et al. (2012)
8.45
8.61
8.50
Concluding remarks
A spectroscopic study of the shock in Stephan’s Quintet has revealead
the existence of two kinematical components associated to this region.
The low-velocity component shows a velocity gradient from 5700 to
6200km/s and could be the link between the HI filaments NW-LV and
SW.
(Originally part of NGC7318b?)
The high-velocity component shows a velocity consistent with NW-HV.
(Originally part of NGC7319?, primordial filament?).
We need higher spectral resolution bi-dimensional spectra with higher
signal-to-noise ratio: MEGARA @ GTC, HEXA (CAHA) are promissing
facilities that will provide best-quality data to study these structures in
more detail.