bluuebunny/crossref_metadata_2025_split huggingface dataset:
Kinematics of the Circumnuclear Region of NGC 3351
Authors: Díaz A. I. , Hägele G. F. , Cardaci M. V. , Terlevich E. , Terlevich R. 
Published: April 2007

AbstractUsing high-resolution blue and far red spectra from the William Herschel Telescope, we have mapped the velocity field along three different slits in the central kiloparsec of the spiral galaxy NGC 3351. We have measured ionized gas (Hβ and [Oiii]) and stellar (near-IR Ca triplet) velocity dispersions for five individual Circumnuclear Star Forming Regions (CNSFRs) and the nucleus. Velocities and velocity dispersions in the red range were obtained using the cross-correlation technique of Tonry & Davis (1979AJ.84.1511) with a set of eleven templates, following the work by Nelson & Whittle (1995.ApJSS.99.67) with the variations introduced by Palacios et al. (1997.A & A.323.749). The gas velocities and velocity dispersions have been measured by fitting gaussians to the emission lines (Hβ and [OIII] λ5007Å) using three different suitable continua chosen by visual inspection and taking the average of the three results (Jiménez-Benito et al., 2000.MNRAS.317.907).The rotation velocities derived for gas and stars are in very good agreement, although in some cases the gas seems to rotate slightly faster than stars. The turnover points of the rotational curves seem to be located at the same position than the star forming ring as found in other galaxies (Díaz, R. et al., 1999ApJ.512.623). The derived values are consistent with those previously obtained for the systemic velocity of NGC 3351 (Planesas et al., 1997.A & A.325.81).The velocity dispersions of the stars are always larger (by between 10 and 25 km/sec) than those derived from Hβ emission lines. In the cases in which it has been possible to use the Paschen emission lines, the results obtained are similar. The twice ionized oxygen, on the other hand, shows velocity dispersions comparable to the stellar ones or, in some cases, even larger. It is however important to point out that in these metal rich regions the [Oiii] lines are very weak and they have a poor signal to noise ratio, then it is more difficult to accurately estimate the global kinematic behaviour from this emission line.The difference between the behavior of ionized hydrogen and stars could be interpreted by assuming that the gas is confined to the disc and supported by rotation while the stars are mostly supported by dynamical pressure (see Pizzella et al., 2004.A & A.424.447). However, the kinematics of ionized gas as mapped by [Oiii], as we mentioned above, is similar to that of the stellar component.We have applied the virial theorem to estimate the dynamical masses of the clusters and the galactic nucleus, assuming that the systems are gravitationally bound and spherically symmetric, and using sizes measured from the HST-WFPC2 image in the F606W filter (sizes between 2.6 and 5.1 pc). These values of the masses, estimated from stellar velocity dispersion measurements as mapped by the CaT lines, are in the range between 5.1×106 and 5.0×107 M⊙ for the five studied CNSFRs and 3.6×107 M⊙ for the nucleus of the galaxy, in the inner 23.4 pc.
A Link in SFR and Morphology of Bulges
Authors: Fisher David B. 
Published: April 2007

AbstractWe use Spitzer 3.6-8.0 μm color profiles to compare the radial structure of star formation of galaxies with pseudobulges and classical bulges. Galaxies structurally identified as having pseudobulges have higher central star formation rates than those of classical bulges. Further, galaxies identified as having classical bulges have remarkably regular star formation profiles. These observations support the picture of pseudobulge formation via secular evolution and classical bulges forming in mergers.
Star-Forming Regions in the SMC
Authors: Gonidakis I. , Livanou E. , Kontizas E. , Klein U. , Kontizas M. , Kester D. , Fukui Y. , Mizuno N. , Tsalmantza P. 
Published: April 2007

AbstractSMC has been going through an active star formation epoch, especially during the last 0.2 Gyr when the close encounter with the LMC occured. Our goal is to detect regions dominated by early-type stars and gas and examine their behaviour at different wavelengths. Spectral energy distributions, a colour-magnitude diagram and a two-colour diagram from IRAS data (Bontekoe, Koperet & Kester (1994); Bontekoe, Kester, Stanimirović, et al. (1999)) for these regions were used in order to compare their properties with those of starburst galaxies (Helou (1986); Lehnert & Heckman (1995)). We have selected 50 stellar complexes with increased 100-μm IRAS flux, with detetected emission in all IRAS bands and/or high concentration of young stars. Ranking them by size (Maragoudaki, Kontizas, Kontizas, et al. (1998)), a total of what we call 24 aggregates, 23 complexes and 3 super-complexes were found. Radio continuum maps at 8.6-GHz (Haynes, Murray, Klein, et al. (1986)) and the CO (1→0) line (Mizuno, Rubio, Mizuno, et al. (2001)) were also correlated with the map of the complexes. Only 8 of them show enhanced star formation activity according to their IR properties and 8.6-GHz map, however, none of them resembles the IR behaviour of starburst regions found in the LMC and starburst galaxies (Livanou, Kontizas, Gonidakis, et al. (2006)). The south-west part of the “bar” has the most diverse intensity of star formation, with CO emission coincident with the largest structure. In the north-eastern end of the “bar”, star formation is likely to have commenced in the recent past, with molecular gas being abundant in this region. Ongoing and future star formation are revealed in the wing, while it appears to have ceased in the central “bar”.
A Possible Detection of CO (J = 3–2) Emission From the Host Galaxy of GRB 980425 with Atacama Submillimeter Telescope Experiment
Authors: Hatsukade Bunyo , Kohno Kotaro , Endo Akira , Tosaki Tomoka , Ohta Kouji , Sakamoto Seiichi , Kawai Nobuyuki , Cortés Juan R. , Nakanishi Kouichiro , Okuda Takeshi , Muraoka Kazuyuki , Sakai Takeshi , Ezawa Hajime , Yamaguchi Nobuyuki , Kamegai Kazuhisa , Kawabe Ryohei 
Published: April 2007

AbstractLong-duration gamma-ray bursts (GRBs) are considered to be due to the death of massive stars. Therefore, GRBs are closely associated with the star formation of host galaxies. Since GRBs can be detected at cosmological distances, they are expected to be probes of the star formation history of the Universe. In order to determine the use of GRBs, it is essential to understand the star formation of their hosts. Multi-wavelength observations have shown that the star formation rates (SFRs) of GRB hosts derived from submillimeter/radio observations are generally higher than those from optical/UV observations (Berger et al. 2003). This implies that GRB hosts have a large amount of molecular gas and massive star formation obscured by dust. In order to solve this problem, it is necessary to derive the SFRs in a method which is independent of existing methods and not affected by dust extinction.We observed 12CO (J = 3–2) line emission from the host galaxy of GRB 980425 using the Atacama Submillimeter Telescope Experiment (ASTE). Five points were observed covering the entire region of the galaxy, and we find possible emission features (S/N ~ 3 σ) at the velocity range corresponding to the redshift of the galaxy. By combining all spectra of five points, we obtain a global spectrum with a ~4 σ emission feature. If the features are real, this is the first detection of CO among GRB hosts. We derive the total gas mass of M(H2)=7 ± 2× 108M⊙ assuming a CO-to-H2 conversion factor of αCO = 8.0M⊙ (K km s−1 pc2)−1, which is deduced using the correlation between the αCO and the metallicity. The dynamical mass is calculated to be Mdyn=2× 1010M⊙, and M(H2)/Mdyn~3% is consistent with those of nearby dwarfs and normal spirals. The derived SFR is 0.5 ± 0.1 M⊙ yr−1 based on the Schmidt law. This SFR agrees with the results of previous Hα observations, suggesting that there is no significant obscured star formation in this host galaxy. This result implies that there is a variety of GRB hosts in terms of the presence of obscured star formation.
N-Body Simulations of Galaxies: Mass-Loss from Old Stellar Populations and the Mass Budget of the Central Kiloparsec
Authors: Jungwiert Bruno 
Published: April 2007

AbstractWe give estimates of the global mass-loss rate from bulge stars and show that this supply of gas is not negligible for the mass budget of the central kiloparsec in comparison with mass inflow rate predicted by N-body simulations of barred galaxies and mergers.
The Last Stages of Star Formation in dEs?
Authors: Lisker T. , Glatt K. , Westera P. , Grebel E. K. 
Published: April 2007

AbstractA significant fraction of Virgo cluster early-type dwarf galaxies have blue central colours caused by recent or ongoing star formation. A spectral analysis shows that even in their centers, stellar mass is dominated by an old population. These galaxies are an unrelaxed cluster population that possibly formed from morphological transformation of late-type galaxies.
Star-Burst Regions in the LMC
Authors: Livanou E. , Kontizas M. , Gonidakis I. , Kontizas E. , Klein U. , Fukui Y. , Mizuno N. 
Published: April 2007

AbstractFilamentary structures of early type stars are found to be a common feature of the MCs formed ~0.9 − 2 × 108yr ago. As we go to younger ages these large structures appear fragmented and sooner or later form young clusters and associations. In the optical domain we have detected 56 such large structures of young objects, known as stellar complexes in the LMC (Maragoudaki, Kontizas, Kontizas, et al. (1998)) and investigate their properties. IRAS data of the LMC stellar complexes were compared with observations of starburst galaxies (Helou (1986); Lehnert & Heckman (1996)). It has been found that nearly 1/4 of the stellar complexes are extremely active resembling the IR behaviour of starburst galaxies and HII regions. These stellar complexes are called here “starburst regions”. They host an increased number of HII regions, SNRs, stellar associations and nebulae. The main starburst tracers are their IR luminosity F60 and the 8.6-GHz radio emission (8.6-GHz data: Dickel, McIntire, Gruendl, et al. (2005)). In Table 1 the characteristics of the various types of complexes are given. Finally the evolution of all stellar complexes is discussed based on the CO emission (CO data: Fukui, Mizuno, Yamagushi, et al. (1999)). More than 50% of the starburst and starburst candidate regions show enhanced CO emission, indicating ongoing and future evolution.
The Kinematics of Extended Hα Emission in Blue Compact Galaxies
Authors: Marquart T. , Östlin G. , Bergvall N. , Masegosa P. , Amram P. , Márquez I. 
Published: April 2007

AbstractBlue Compact Galaxies (BCGs) have received interest mainly because they comprise the best available test-beds for studies of low-metallicity star formation (SF) and allow the study of relatively unevolved systems at low redshift. Their ongoing phase of intense star formation is a transient phenomenon and the best candidates for its trigger are interactions and mergers. Studies of the kinematics are important for the understanding of this process.We present spatially resolved kinematics from the Hα line in five BCGs that show an extended region of ionised emission around the central starburst. We find this region to have near-spherical isophotes at large radii and to be dynamically decoupled from a central disturbance. A scenario where the strong triggered star formation in the center ionises the surrounding gas cloud, still following its original motions, can qualitatively explain these common features. The poster, including the figures, can be found at http://kern-2pt/thomasmarquart.net/pspdf/prague-marquart.pdf.
Serendipitous Spectroscopic Detection of Faint Galaxies at MIR with the IRC Onboard the AKARI During Its In-orbit PV Period
Authors: Ohyama Y. , Wada T. , Sakon I. , Ishigaki M. , Onaka T. , Oyabu S. ,   AKARI/IRC team
Published: April 2007

AbstractThe InfraRed Camera (IRC) (Onaka et al. 2004), a wide-field (~10 × 10 arcmin2) NIR-MIR 2–26(μm) camera and spectrograph onboard the AKARI (formerly ASTRO-F) space telescope (Murakami et al. 2004), can perform slit-less spectroscopic survey. Many faint galaxies have been serendipitously detected during its in-orbit performance verification period thanks to the power of the slit-less spectroscopy. They are as faint as a few – several mJy in flux, but they can be easily recognized by their prominent spectroscopic features (e.g., PAH). Their redshift (≲0.3) can be measured through spectral template fitting over the features. We can thus obtain their basic information (redshift, activity type, and luminosity) to investigate nature of galaxies out to much greater distance at MIR than before. With the new IRC/AKARI data, we might be able to address some of the most interesting questions on galaxy evolution at z≃0.3–2 (e.g., Genzel & Cesarsky 2000; Peeters et al. 2004; Pearson 2005): What contributes to the excess found in mid-infrared source count studies with ISO/Spitzer surveys? How does the luminosity function evolve with redshift? How do the spectral features (PAH, etc.) evolve with redshift, and how they correlate with MIR and FIS luminosities with each other? We here demonstrate how MIR galaxy spectra thus obtained are useful for investigation of their basic properties.
Chemical evolution and stellar populations in the Sagittarius dwarf Spheroidal Galaxy
Authors: Sbordone L. , Bonifacio P. , Giuffrida G. , Marconi G. , Monaco L. , Zaggia S. 
Published: April 2007

AbstractThe closest neighbour of the Milky Way (MW) the Sagittarius dwarf Spheroidal Galaxy (Sgr dSph) is being tidally destroyed by the interaction with our Galaxy, losing its stellar content along a huge stream clearly detectable within the Halo. This makes the Sgr dSph an ideal laboratory to study at the same time the chemical evolution of dwarf galaxies and their role in building bigger structures such as the MW. Since some years we are studying the stellar populations of the Sgr main body and stream, with particular attention to their detailed chemical composition. We collected detailed abundances (up to 22 elements, O to Eu) for 27 stars in the Sgr dSph main body, 5 in the associated globular cluster Terzan 7, and 12 more in the trailing Sgr tidal arm (UVES@VLT and SARG@TNG data). We are also conducting a large FLAMES@VLT chemical and dynamical analysis aimed at obtaining metallicities, alpha-elements content and radial velocities from automated analysis of the spectra. Finally, we just completed the first large scale photometric and spectroscopic survey of the stellar populations across all the dSph main body extension with VIMOS@VLT, aimed at exploring the variations in stellar populations and at deriving radial velocity memberships for future high resolution spectroscopic analysis. The picture emerging from all these studies portraits a large and extremely complex object, with signs of a long and still unclear evolution. Metallicity varies across three orders of magnitude ([Fe/H] from −3 to 0), CMDs change surprisingly from the core to the outskirts of the galaxy, and the chemical composition of the most metal rich objects show a very characteristic signature, with underabundant alpha elements, deficient Na, underabundant Fe-peak Mn, Co, Ni, Cu and Zn, and strongly enhanced n-capture elements La and Nd. This highly peculiar signature can also be effectively used to recognized stripped populations lost by Sgr in favour of the MW system, as clearly showed by the globular Palomar 12, which shows the same chemical anomalies detected in Sgr dSph.
The San Pedro Mártir Open Cluster Survey: Progress, Techniques, Preliminary Results
Authors: Schuster W. , Michel R. , Dias W. , Tapia-Peralta T. , Vázquez R. , MacFarland J. , Chavarría C. , Santos C. , Moitinho A. 
Published: April 2007

AbstractA CCD UBVRI survey of northern open clusters is being undertaken at San Pedro Mártir, México, and performed using always the same instrumental setup (telescope, CCD, filters), reduction methods, and system of standards of Landolt (1992). To date more than 300 clusters (mostly unstudied previously) have been observed, and about half the data reduced using aperture-photometry and PSF techniques. Our analysis procedures are being refined by studying in detail a small subset of these clusters. For example, the heavily reddened clusters Be80 and Be95 are being examined in the color-color diagrams: (B-V, U-B) and (B-V, R-I) to better understand the problems of curvature and variable reddening. For clusters for which our U data reaches the F-type stars, such as NGC2192 and NGC7296, techniques are being examined for estimating both the reddening E(B-V) and metallicity [Fe/H] via the use of the (U-B) excess. If the clusters also have “red clump” stars, such as NGC1798 and Do02, these procedures can be iterated between the clump and main sequence stars to establish even better the values of E(B-V) and [Fe/H]. Finally, color-magnitude diagrams, such as (B-V, V) and (V-I, V), are being employed together with the SchmidtKaler (1982) colors and Padova isochrones of Girardi et al. (2000) to obtain distances and ages for these clusters. A java-based computer program is being developed to help in the visualization and analysis of these photometric data. This system is capable of displaying each cluster simultaneously in different color-color and color-magnitude diagrams and has an interactive way to identify a star, or group of stars, in one diagram and to see were it falls in the other diagrams, facilitating the elimination of field stars and the apperception of cluster features. This program is capable of displaying up to 16 different diagrams for one cluster and processing up to 20 clusters at the same time. Our aims are the following: (1) a common UBVRI photometric scale for open clusters, (2) an atlas of color-color and color-magnitude diagrams for open clusters, (3) a homogeneous set of cluster reddenings, distances, and ages, (4) an increased number of old and distant open clusters, and (5) a selection of interesting clusters for further study.
Star Forming Galaxies and AGN Hosts: The Seagull Wings
Authors: Stasińska Grazyna , Fernandes Roberto Cid , Mateus Abílio , Sodré Laerte , Asari Natalia V. 
Published: April 2007

AbstractUsing photoionization models applied to the data from the Sloan Digital Sky Survey (SDSS) we propose a physically motivated dividing line in the [OIII]/Hβ vs [NII]/Hα (BPT) diagram between normal star forming (NSF) galaxies and AGN hosts. We also propose a new diagnostic diagram which can be used for optical spectra of galaxies with redshifts up to z= 1.3.
Statistical Studies on the Visible and Hidden Star Formation in the Universe
Authors: Takeuchi T. T. , Buat V. , Burgarella D. , Iglesias-Páramo J. 
Published: April 2007

AbstractWe select far-infrared (60 μm) and far-ultraviolet (1530Å) samples of nearby galaxies. We derived distributions of the bolometric luminosity of young stars in both samples: they are found to be consistent with each other for galaxies of intermediate luminosities but some differences are found for high (>5 × 1010L⊙) luminosities. The ratio of the total IR luminosity to the FUV one is found to increase with the bolometric luminosity in a similar way for both samples up to 5 × 1010L⊙. Brighter galaxies are found to have a different behavior according to their selection: the LTIR/LFUV ratio of the FUV selected galaxies brighter than 5 × 1010L⊙ reaches a plateau whereas LTIR/LFUV continues to increase with the luminosity of bright galaxies selected in FIR. The volume averaged specific star formation rate (SFR per unit galaxy stellar mass, SSFR) is found to decrease toward massive galaxies within each selection. The SSFR is found larger than that measured for optical and NIR selected sample for the whole mass range for the FIR selection and for masses larger than 1010M⊙ for the FUV selection. Luminous and massive galaxies selected in FIR appear as active as galaxies with similar characteristics detected at z ~ 0.7. Details are presented in Buat et al. (2006).
First consistent Lyα profile and UV spectral modeling of z ~ 3 LGBs with a 3D radiative transfer code
Authors: Verhamme A. , Schaerer D. , Atek H. 
Published: April 2007

AbstractWe developped a 3D Monte Carlo Lyα radiation transfer code to understand the diversity of Lyα line profiles observed in star forming galaxies and related objects (Verhamme et al. 2006). Our code allows for prescribed arbitrary hydrogen density, ionisation, temperature structures, and dust distributions, and arbitrary velocity fields and UV photon sources.Here we present results from the first modelling of the Lyα line and of the UV spectrum with our code of a sample of z ~ 3 Lyman break galaxies observed by Steidel and collaborators (Pettini et al. 2002) and taken from the FORS Deep Field (Tapken et al. 2006). A simple model of an expanding neutral shell surrounding a starburst region can reproduce the whole variety of spectra ranging from double-peaked profiles to asymetric emission lines, P-Cygni profiles or broad absorption. The main determining parameters are the outflow velocity and the dust content. Other parameters such as the hydrogen column density, the intrinsic Lyα emission and hence SFR, and the intrinsic Lyα line widths can be determined consistently taking all radiation transfer effects into account.
When do early-type galaxies form?
Authors: Abraham Roberto G. , McCarthy Patrick J. , Mentuch Erin , Glazebrook Karl , Nair Preethi , Gauthier Jean-René , Savaglio Sandra , Crampton David , Juneau Stephanie , Murowinski Richard , Le Borgne Damien , Carlberg R. G. , Jørgensen Inger , Roth Kathy , Chen Hsiao-Wen , Marzke Ronald O. 
Published: April 2007

AbstractWe have used the Hubble Space Telescope's Advanced Camera for Surveys to measure the mass density function of morphologically-selected early-type galaxies in the Gemini Deep Deep Survey fields, over the redshift range 0.9 < z < 1.6. Our imaging data set covers four well-separated sight-lines, and is roughly intermediate (in terms of both depth and area) between the GOODS/GEMS imaging data, and the images obtained in the Hubble Deep Field campaigns. Our images contain 144 galaxies with ultra-deep spectroscopy, and they have been analyzed using a new purpose-written morphological analysis code which improves the reliability of morphological classifications by adopting a ‘quasi-petrosian’ image thresholding technique. We find that at z = 1 approximately 70% of the stars in massive galaxies reside in early-type systems. This fraction is remarkably similar to that seen in the local Universe. However, we detect very rapid evolution in this fraction over the range 1.0 < z < 1.6, suggesting that in this epoch the strong color-morphology relationship seen in the nearby Universe is beginning to fall into place.
CATS: CfAO Treasury Survey of distant galaxies, supernovae, and AGN's
Authors: Koo David C. , Melbourne Jason , Max Claire , Metevier Anne , Ammons Mark , Larkin James E. , Barczys Matthew , Wright Shelley A. , Steinbring Eric 
Published: April 2007

AbstractThe NSF Science and Technology Center for Adaptive Optics (CfAO) is supporting a major scientific legacy project called the CfAO Treasury Survey (CATS). CATS is obtaining near-infrared AO data in deep HST survey fields, such as GEMS, GOODS-N, & EGS. Besides summarizing the main objectives of CATS, we highlight some recent imaging work on the study of distant field galaxies, AGNs, and a redshift z = 1.32 supernova. CATS plans the first data release to the community in early 2007 (check http://www.astro.ucla.edu/~irlab/cats/index.shtml for more details on CATS and latest updates).