Self-consistent Bulge/Disk/Halo Galaxy Dynamical Modeling Using Integral Field Kinematics

We introduce a method for modeling disk galaxies designed to take full advantage of data from integral field spectroscopy (IFS). The method fits equilibrium models to simultaneously reproduce the surface brightness, rotation, and velocity dispersion profiles of a galaxy. The models are fully self-consistent 6D distribution functions for a galaxy with a Sérsic profile stellar bulge, exponential disk, and parametric dark-matter halo, generated by an updated version of GalactICS. By creating realistic flux-weighted maps of the kinematic moments (flux, mean velocity, and dispersion), we simultaneously fit photometric and spectroscopic data using both maximum-likelihood and Bayesian (MCMC) techniques. We apply the method to a GAMA spiral galaxy (G79635) with kinematics from the SAMI Galaxy Survey and deep g- and r-band photometry from the VST-KiDS survey, comparing parameter constraints with those from traditional 2D bulge–disk decomposition. Our method returns broadly consistent results for shared parameters while constraining the mass-to-light ratios of stellar components and reproducing the H i-inferred circular velocity well beyond the limits of the SAMI data. Although the method is tailored for fitting integral field kinematic data, it can use other dynamical constraints like central fiber dispersions and H i circular velocities, and is well-suited for modeling galaxies with a combination of deep imaging and H i and/or optical spectra (resolved or otherwise). Our implementation (MagRite) is computationally efficient and can generate well-resolved models and kinematic maps in under a minute on modern processors

ProFit : Bayesian profile fitting of galaxy images

We present ProFit, a new code for Bayesian two-dimensional photometric galaxy profile modelling. ProFit consists of a low-level c++ library (libprofit), accessible via a command-line interface and documented API, along with high-level R (ProFit) and Python (PyProFit) interfaces (available at github.com/ICRAR/libprofit, github.com/ICRAR/ProFit, and github.com/ICRAR/pyprofit, respectively). R ProFit is also available pre-built from cran; however, this version will be slightly behind the latest GitHub version. libprofit offers fast and accurate two-dimensional integration for a useful number of profiles, including Sérsic, Core-Sérsic, broken-exponential, Ferrer, Moffat, empirical King, point-source, and sky, with a simple mechanism for adding new profiles. We show detailed comparisons between libprofit and galfit. libprofit is both faster and more accurate than galfit at integrating the ubiquitous Sérsic profile for the most common values of the Sérsic index n (0.5 < n < 8). The high-level fitting code ProFit is tested on a sample of galaxies with both SDSS and deeper KiDS imaging. We find good agreement in the fit parameters, with larger scatter in best-fitting parameters from fitting images from different sources (SDSS versus KiDS) than from using different codes (ProFit versus galfit). A large suite of Monte Carlo-simulated images are used to assess prospects for automated bulge-disc decomposition with ProFit on SDSS, KiDS, and future LSST imaging. We find that the biggest increases in fit quality come from moving from SDSS- to KiDS-quality data, with less significant gains moving from KiDS to LSST.Publisher PDFPeer reviewe

Self-consistent Bulge/Disk/Halo Galaxy Dynamical Modeling Using Integral Field Kinematics

We introduce a method for modeling disk galaxies designed to take full advantage of data from integral field spectroscopy (IFS). The method fits equilibrium models to simultaneously reproduce the surface brightness, rotation, and velocity dispersion profiles of a galaxy. The models are fully self-consistent 6D distribution functions for a galaxy with a Sérsic profile stellar bulge, exponential disk, and parametric dark-matter halo, generated by an updated version of GalactICS. By creating realistic flux-weighted maps of the kinematic moments (flux, mean velocity, and dispersion), we simultaneously fit photometric and spectroscopic data using both maximum-likelihood and Bayesian (MCMC) techniques. We apply the method to a GAMA spiral galaxy (G79635) with kinematics from the SAMI Galaxy Survey and deep g- and r-band photometry from the VST-KiDS survey, comparing parameter constraints with those from traditional 2D bulge–disk decomposition. Our method returns broadly consistent results for shared parameters while constraining the mass-to-light ratios of stellar components and reproducing the H i-inferred circular velocity well beyond the limits of the SAMI data. Although the method is tailored for fitting integral field kinematic data, it can use other dynamical constraints like central fiber dispersions and H i circular velocities, and is well-suited for modeling galaxies with a combination of deep imaging and H i and/or optical spectra (resolved or otherwise). Our implementation (MagRite) is computationally efficient and can generate well-resolved models and kinematic maps in under a minute on modern processors

ProFound : source extraction and application to modern survey data

Parts of this research were conducted by the Australian Research Council Centre of Excellence for All-sky Astrophysics (CAASTRO), through project number CE110001020.We introduce ProFound, a source finding and image analysis package. ProFound provides methods to detect sources in noisy images, generate segmentation maps identifying the pixels belonging to each source, and measure statistics like flux, size and ellipticity. These inputs are key requirements of ProFit, our recently released galaxy profiling package, where the design aim is that these two software packages will be used in unison to semi-automatically profile large samples of galaxies. The key novel feature introduced in ProFound is that all photometry is executed on dilated segmentation maps that fully contain the identifiable flux, rather than using more traditional circular or ellipse based photometry. Also, to be less sensitive to pathological segmentation issues, the de-blending is made across saddle points in flux. We apply ProFound in a number of simulated and real world cases, and demonstrate that it behaves reasonably given its stated design goals. In particular, it offers good initial parameter estimation for ProFit, and also segmentation maps that follow the sometimes complex geometry of resolved sources, whilst capturing nearly all of the flux. A number of bulge-disc decomposition projects are already making use of the ProFound and ProFit pipeline, and adoption is being encouraged by publicly releasing the software for the open source R data analysis platform under an LGPL-3 license on GitHub (github.com/asgr/ProFound).PostprintPeer reviewe

The SAMI Galaxy Survey: the intrinsic shape of kinematically selected galaxies

Using the stellar kinematic maps and ancillary imaging data from the Sydney AAO Multi Integral field (SAMI) Galaxy Survey, the intrinsic shape of kinematically-selected samples of galaxies is inferred. We implement an efficient and optimised algorithm to fit the intrinsic shape of galaxies using an established method to simultaneously invert the distributions of apparent ellipticities and kinematic misalignments. The algorithm output compares favourably with previous studies of the intrinsic shape of galaxies based on imaging alone and our re-analysis of the ATLAS3D data. Our results indicate that most galaxies are oblate axisymmetric. We show empirically that the intrinsic shape of galaxies varies as a function of their rotational support as measured by the "spin" parameter proxy Lambda_Re. In particular, low spin systems have a higher occurrence of triaxiality, while high spin systems are more intrinsically flattened and axisymmetric. The intrinsic shape of galaxies is linked to their formation and merger histories. Galaxies with high spin values have intrinsic shapes consistent with dissipational minor mergers, while the intrinsic shape of low-spin systems is consistent with dissipationless multi-merger assembly histories. This range in assembly histories inferred from intrinsic shapes is broadly consistent with expectations from cosmological simulations.Comment: 15 pages, 11 figures, MNRAS in prin

Classic and modern in the therapy of hepatic hidatid cysts – experience of a general surgery center

Clinica II Chirurgie, Spitalul Județean de Urgențe ”Sf. Spiridon”, Iași UMF ”Gr.T. Popa” Iași, Al XI-lea Congres al Asociației Chirurgilor „Nicolae Anestiadi” din Republica Moldova și cea de-a XXXIII-a Reuniune a Chirurgilor din Moldova „Iacomi-Răzeșu” 27-30 septembrie 2011INTRODUCERE. În ultimii 20 de ani, asistăm la o tendință de afirmare a terapiilor mai puțin invazive pentru pacienții cu chist hidatic hepatic (radiologie intervențională, endoscopie intervențională, puncții eco sau CT-ghidate, tehnici chirurgicale laparoscopice precum şi asocieri ale acestora). SCOP. Ne-am propus o comparație între rezultatele după abordul clasic şi cel minim-invaziv pentru tratamentul echinococozei hepatice. MATERIAL ŞI METODĂ. Au fost analizate retrospectiv 180 cazuri de chist hidatic hepatic operate în Clinica I Chirurgie Iaşi, România în perioada 2004-2010. Au fost selectate pentru analiză următoarele variabile: localizarea chistului, tipul acestuia (conform clasificării propuse de Informal Working Group on Echinococcosis), calea de abord, tehnica chirurgicală, durata evoluției postoperatorii, complicațiile survenite, recidivele şi asocierea chimioterapiei antiparazitare. Pentru analiza statistică s-au folosit testele neparametrice Mann-Whitney U şi Spearman cu pragul de semnificație p<0.05. REZULTATE. Leziunile s-au tratat prin puncție echoghidată (n=6;3.3%); pe cale laparoscopică (n= 48;26.6%) şi abord clasic (n=126;70.1%). Pe cale laparoscopică s-au efectuat: inactivare-aspirație-drenaj şi inactivare-aspirație-perichistectomie parțială. Pe cale clasică s-au practicat: inactivare-aspirație-drenaj, inactivare-aspirație-perichistectomie parțială, perichistectomie ideală, hepatectomie reglată, hepatectomie atipică. Abordul minim-invaziv se corelează semnificativ cu tipul I-II al chisturilor (p=0.016) şi cu localizarea acestora în segmentele II, III şi VI (p=0.001). Durata evoluției postoperatorii a fost semnificativ mai redusă după abordul laparoscopic (p=0.003) comparativ cu cea după intervențiile clasice „minimale” (inactivare-aspirație-drenaj şi inactivare-aspirație-perichistectomie parțială) practicate pentru leziunile tip I-III, dar diferența dintre numărul de zile de îngrijiri după abordul laproscopic vs. chirurgie radicală (perichistectomie ideală, hepatectomie) este nesemnificativă. Nu am întâlnit corelații semnificative între apariția recidivelor/complicațiilor şi tipul de abord. Chimioterapia antiparazitară, instituită în 118 de cazuri (65.5%), se corelează semnificativ cu o rată redusă a recidivelor survenite în 9 cazuri (5%). CONCLUZII. Boala hidatică beneficiază astăzi de o terapie multimodală în care chimioterapia, PAIR-ul, videochirurgia şi chirurgia clasică trebuie să se completeze cât mai fericit şi nu să se excludă. Chiar dacă „pierde din indicații”, chirurgia clasică rămâne „rezerva strategică” în terapia chistului hidatic.INTRODUCTION. In the last 20 years, we noticed an outstanding of less invasive therapy for the patients with hidatid disease (interventional radiology, interventional endoscopy, eco- or CT punctions, laparoscopy and association between these). AIM. We intend to compare the results after classic and laparoscopic approach as treatment for hepatic echinococcosis. METHODS. We analysed 180 cases operated in 1st Surgical Clinic, Iasi, Romania, between 2004-200. We recorded the fallowing parameters: location, type (classification approved by Informal Working Group on Echinococcosis), approaching type, surgical technique, postoperative evolution, complications, recurrences and chemotherapy. We used Mann-Whitney U and Spearman tests (p<0.05).RESULTS. The cases were solved by eco guidance punction (n=6; 3.3%); laparoscopic (n= 48; 26.6%) and classic approach (n=126; 70.1%). Minim invasive approach we did inactivation-suction-drainage and partial perichistectomy. Using open approach we did inactivation-suction-drainage, partial perichistectomy, total perichistectomy and hepatectomy. Laparoscopic treatment has significant correlation with type I-II (p=0.016) located in segments II, III and IV (p=0.001). Postoperative evolution is significant lower for laparoscopic methods (p=0.003) comparing with the „minimal” open techniques used for lesions type I-III. There is no significant differentiation between laparoscopic procedures and open radical surgery (total perichistectomy and hepatectomy). We did not register significant correlations about recurrences and complications. Chemotherapy used in 8 cases is correlated with a low rate of recurrence 9 cases (5%).CONCLUSIONS. Hidatid disease has the benefits of a multimodal therapy. Chemotherapy, PAIR, video surgery and open approach are completing themselves and not excluding each other. Even if classic methods are less frequent used, it remains as a „back up solution” in the therapy of hidatid cyst disease

Femtosecond laser internal structuring of materials using a spatial light modulator

Femtosecond laser pulses are of particular interest for internal modification of transperent materials as they enable nonlinear absorption due to the extremly high intensity in the focal volume. Since output from commercial laser sources currently exceeds single beam process requirements, parallel processing with multiple beams could provide a route to up-scaling processing speed and establish cost-effectiveness. The use of spatial light modulators, driven by fast computer-generated holograms for splitting a parent laser beam into a number of beamlets and digitally manipulate their positions and the laser intensity is demonstrated. With successful blocking of the zero order beam and subsequent focusing of the diffracted beams inside transperant materials, high throughput dynamic 2D/3D refractive index modification of polymer and glass substrates with a gain factor G > 20 has been achieved. Fundamental IR (775nm) femtosecond laser pulses were employed to produce optical components. For example, thick volume gratings written with more than 20 beams have 1st order diffraction efficiency η > 60%, indicating a refractive index change Δn ≈ 1.6x10-4. Characterization by microscopic examination and light coupling tests revealed the extent of resolution, process quality and assisted quantification of the process speed gain. The benefits and current limitations of this technique are discussed in detail

Self-consistent bulge/disk/halo galaxy dynamical modeling using integral field kinematics

We introduce a method for modeling disk galaxies designed to take full advantage of data from integral field spectroscopy (IFS). The method fits equilibrium models to simultaneously reproduce the surface brightness, rotation, and velocity dispersion profiles of a galaxy. The models are fully self-consistent 6D distribution functions for a galaxy with a Sérsic profile stellar bulge, exponential disk, and parametric dark-matter halo, generated by an updated version of GalactICS. By creating realistic flux-weighted maps of the kinematic moments (flux, mean velocity, and dispersion), we simultaneously fit photometric and spectroscopic data using both maximum-likelihood and Bayesian (MCMC) techniques. We apply the method to a GAMA spiral galaxy (G79635) with kinematics from the SAMI Galaxy Survey and deep g- and r-band photometry from the VST-KiDS survey, comparing parameter constraints with those from traditional 2D bulge–disk decomposition. Our method returns broadly consistent results for shared parameters while constraining the mass-to-light ratios of stellar components and reproducing the H i-inferred circular velocity well beyond the limits of the SAMI data. Although the method is tailored for fitting integral field kinematic data, it can use other dynamical constraints like central fiber dispersions and H i circular velocities, and is well-suited for modeling galaxies with a combination of deep imaging and H i and/or optical spectra (resolved or otherwise). Our implementation (MagRite) is computationally efficient and can generate well-resolved models and kinematic maps in under a minute on modern processors.Publisher PDFPeer reviewe