Enrica Bellocchi 21 November 2016, Universidad Autnoma de Madrid 1 - PowerPoint PPT Presentation

Enrica Bellocchi 21 November 2016, Universidad Autónoma de Madrid 1

“SELGIFS” (international collaboration focused on the Study of Emission-Line Galaxies with Integral-Field Spectroscopy) 2

Main objecCve “Study of potenCal systemaCc effects on the derivaCon of pure gas kinemaCc parameters” … focusing on the differences arising from the way the stellar continuum is subtracted as well as the presence of non-Gaussian line profiles and/or multiple kinematic components Integral Field Spectroscopy (IFS) is the suitable technique to record SIMULTANEOUSLY spaCally resolved spectra over a 2D field ! 3

The role of the spaCally resolved kinemaCcs 2D kinemaCc characterizaCon of galaxies provides a powerful diagnosCc: 1) to infer the main source of dynamical support (v/σ <, > 1); 2) to disCnguish between relaxed virialized systems and merger events; 3) to detect and characterized radial moCon associated with feedback mechanisms (like ou^lows); 4) to infer fundamental quanCCes like dynamical masses; 5) to constrain modes of star-formaCon (mergers vs steady cool gas accreCon) in galaxies with ambiguous morphologies: Major merger � complex morphology and kinemaCcs (mergers) � Steady accreCon � regular morphology and kinemaCcs (disks) � But.. In some cases we see irregular morphology characterized by regular � kinemaCcs!! Morphology could be misleading…. 4

Main general steps of this work Stellar conCnuum subtracCon 1 ) To derive the pure gas kinemaCcs (Hα) we have to perform the stellar conCnuum substracCon Line figng analysis λ 1 , σ 1 2 ) To characterize the Hα profile (λ, σ) and λ 2 , σ 2 reveal non-Gaussian profiles (secondary broad component � ou^low, SN event…) 5

GeneraCon of the kinemaCc maps: Hα v elocity field and velocity dispersion maps NGC 2906 (gas + stellar emission) CompuCng the kinemaCc parameters e.g., dynamical raCo v/σ, velocity amplitude, central velocity dispersion, etc Comparing the v/σ results among different methods and discussion … 6

Things to do (I) The target -- We select one galaxy from the AMUSING survey (Lluis Galbany): NGC 2906 � spiral galaxy, z = 0.07138 (v sys = 2140 km/s) + SN2005ip studied at different wavelengths Data analysis -- We select the preferred tools to remove the stellar conCnuum (Wednesday’s talks!): maybe, we are mainly interested in Starlight, pyParadise, Pipe3D … -- Apply these tools to generate the pure gas cubes 7

Things to do (II) Line figng analysis we focus on Ha + [NII] λλ6548, 6583 Å lines to derive the velocity field and velocity dispersion maps (v, d) 1) Spectra fived automaCcally to (single) Gaussian profiles using an IDL/python rouCne (MPFITEXPR) [Method 1] -- The total emission = conCnuum (straight line + slope) + 3 (6) Gaussians -- The three lines are kinemaCcally linked: they follow the same kinemaCcs (λ Ha – λ NII ) obs = (1 + z) x (λ Ha – λ NII ) em λ 1 , σ 1 σ Ha = σ NII and σ Ha , σ NII > σ INST λ 2 , σ 2 -- The flux raCos are fixed according to atomic physics: Flux [NII] λ6583 Å : Flux [NII] λ6548 Å = 3:1 Aim: to derive λ Ha ( � v Ha ) and σ Ha ( � velocity dispersion) and 8 flux intensity of the line and generate their relaCve maps!

Things to do (II contd) Line figng analysis 2) Bayesian line figng approach [Method 2] CompuCng the likelihood in reproducing the observed data when considering L (Data| v model , σ model ) = ? different models for each line: -- For each line and for each spaxel we compute L using different models (v model , σ model ) -- We derive the mean value of L in each spaxel and extrapolate the velocity field and velocity dispersion maps associated to such L. Wavelength λ L 1 ( v 1 mod , σ 1 mod ) (… but it is quite Cme consuming when consdering a Width σ large quanCty of spectra, as when using MUSE data!) L 2 ( v 2 mod , σ 2 mod ) 3) Try to use other line figng methods will be described during the school ! 9

Products of the line figng analysis : e.g., velocity field map 1) CALIFA (only gas emission, R ~ 850, 1”/spaxel): stellar conCnuum subtracted by Ruben García Benito using STARLIGHT [line figng Method 1] NGC 2906 CALIFA Gas + stars [NII] Hα [NII] --------------- Only gas 2) MUSE (gas + stars emissions, R~3000, 0.2”/spaxel): from AMUSING (Lluis Galbany) [line figng Method 2] NGC 2906 MUSE Gas + stars --------------- [NII] Hα [NII] FoV 1’x1’ Only gas 10

With CALIFA data: only gas emission + 2 component figng NGC 2906 Narrow comp Broad comp (SN2005ip) 11

KinemaCc results from 2-D data 1-D kinemaCc results derived from 2-D kinemaCc data � � derive 1-D kinemaCc parameters for the narrow and broad components (dynamical raCo v/σ, v, σ) & comparison with other local samples 2-D kinemaCc results � characterizCon of the � kinemaCc asymmetries using “kinemetry” to disCnguish between disks and mergers (v asym , σ asym ) (in the next future… e.g., Bellocchi+2016) 12

Things to do (III) v amp = 0.5 (v max – v min ) v shear = 0.5 (v 5% max – v 5% min ) Derive mean kinemaCc values � σ mean mean velocity dispersion σ c central velocity dispersion Compare the (v, σ) results derived using the different tools � (U)LIRGs Sp LBA E/S0 Bellocchi+2013 13

Summary � The target: NGC 2906 obserbed with MUSE (AMUSING survey, Lluis Galbany) � Select the preferred tools (stellar conCnuum subtracCon): Starlight, Pipe3D… � GeneraCon of the pure gas cubes � Line figng analysis (using the methods proposed in the school) � Generate the v, σ maps: - Is there any evidence of a broad secondary component? � Compute the kinemaCc parameters (v shear , σ mean , v/σ) and compare them when using different approach. Draw your conclusions! Future work Bever kinemaCc characterizaCon of the broad component o ApplicaCon of the “kinemetry” method to quanCfy the kinemaCc asymmetries o v asym , σ asym in the derived velocity field and velocity dispersion maps Study any kinemaCc relaConships between the different gas phases (if present) o 14

Summary � The target: NGC 2906 obserbed with MUSE (AMUSING survey, Lluis Galbany) � Select the preferred tools (stellar conCnuum subtracCon): Starlight, Pipe3D… � GeneraCon of the pure gas cubes d n a s ’ w o r r � Line figng analysis (using the methods proposed in the school) o m o t & r o s f k g l a n t C s � Generate the v, σ maps: i ’ a y ! W a ! ! d e s s e a n c d e e c W - Is there any evidence of a broad secondary component? n e i c s a n o - � Compute the kinemaCc parameters (v shear , σ mean , v/σ) and compare them when s k r o W using different approach. Draw your conclusions! Future work Bever kinemaCc characterizaCon of the broad component o ApplicaCon of the “kinemetry” method to quanCfy the kinemaCc asymmetries o v asym , σ asym in the derived velocity field and velocity dispersion maps Study any kinemaCc relaConships between the different gas phases (if present) o 15