18 research outputs found
V, R, I and Halpha photometry of circumnuclear star forming regions in four galaxies with different levels of nuclear activity
V,R,I continuum bands and Halpha + [NII] photometry for circumnuclear star
forming regions (CNSFR) is presented, for galaxies with different kinds of
nuclear activity: NGC 7469 (Sy 1), NGC 1068 (Sy 2), NGC 7177 (LINER) and NGC
3310 (Starburst). Their Halpha luminosities (0.02 - 7x10**40 erg/s; uncorrected
for internal extinction), are comparable to those observed in other galaxies.
No systematic differences in the broad band colours are found for the CNSFR in
the different galaxies, except for those in NGC 3310 which are considerably
bluer, partially due to a younger stellar population. Using theoretical
evolutionary synthesis models some colours can be reproduced by single
populations (between 7 and 300 Myr) and extinction 0.5-1.5 mag). However, in
many cases, the observed equivalent width of Halpha, require a younger
population. NGC 1068, 7177 and 7469, are fitted by a two-burst population model
at solar metallicity; the age difference between both populations is around 5-7
Myr and the younger burst involves 3 - 61% of the total mass of the
cluster,consistent with the younger burst being originated by supernova
activity from the previous one. NGC 3310, requires younger ionizing population
ages and lower metallicity. An excess (R-I) observed/predicted, not consistent
with a normal reddening law can be atributted to red supergiants present in the
older population, and not properly accounted for by the models. The
two-population scenario seems to show a trend of the evolutionary state of the
CNSFR with the nuclear type of the parent galaxy that remains to be explored.Comment: Accepted for publication in MNRAS, 22pages, 11 figure
Search for H alpha emitters in Galaxy Clusters with Tunable Filters
The studies of the evolution of galaxies in Galaxy Clusters have as a
traditional complication the difficulty in establishing cluster membership of
those sources detected in the field of view. The determination of spectroscopic
redshifts involves long exposure times when it is needed to reach the cluster
peripherical regions of/or clusters at moderately large redshifts, while
photometric redshifts often present uncertainties too large to offer
significant conclusions. The mapping of the cluster of galaxies with narrow
band tunable filters makes it possible to reach large redshifts intervals with
an accuracy high enough to establish the source membership of those presenting
emission/absorption lines easily identifiable, as H alpha. Moreover, the
wavelength scan can include other lines as [NII], [OIII] or
allowing to distinguish those sources with strong stellar formation activity
and those with an active galactic nuclei. All this makes it possible to
estimate the stellar formation rate of the galaxies observed. This, together
with ancillary data in other wavelengths may lead to a good estimation of the
stellar formation histories. It will shed new light over the galaxy evolution
in clusters and will improve our understanding of galaxy evolution, especially
in the outer cluster regions, usually less studied and with significant
unexploited data that can not be correctly interpreted without redshift
determination.Comment: 4 pages, 2 figures. "Highlights of Spanish Astrophysics V",
Proceedings of the VIII Scientific Meeting of the Spanish Astronomical
Society (SEA) held in Santander, 7-11 July, 200
La rotación de personal de serenazgo de la Subgerencia de Serenazgo de la Gerencia de Seguridad Ciudadana de la Municipalidad Distrital de Miraflores, dentro del Plan Estratégico Distrital de Seguridad Ciudadana del año 2018 como un indicador de gestión
El presente trabajo de investigación refiere a la rotación de personal de serenazgo de la Subgerencia de Serenazgo de la Gerencia de Seguridad Ciudadana de la Municipalidad Distrital de Miraflores dentro del Plan Estratégico Distrital de Seguridad Ciudadana del año 2018 como un indicador de gestión, siendo que dicha comuna tiene como domicilio fiscal sito en la Av. Larco N° 400, Miraflores - Lima.
Los resultados que se obtengan en el presente estudio nos permitirá conocer las posibles causas que da origen a este fenómeno, toda vez que viene afectando el cumplimiento del objetivo general del Plan Estratégico Distrital de Seguridad Ciudadana del 2018, que establece: “Fortalecer el trabajo multisectorial en el distrito mediante la interrelación, capacitación, asistencia técnica y administrativa de los sectores e instituciones comprometidas, con la participación de la comunidad organizada, a fin de mejorar los niveles de percepción de seguridad ciudadana”.
La hipótesis general del presente estudio señala que: “La insatisfacción en el trabajo percibido por el personal de serenazgo aumentará el índice de rotación del personal”; por lo que, a través de una contrastación, se obtendrá los resultados respectivos, y que en el contenido de las conclusiones y recomendaciones se pondrá de manifiesto las causas que originan la rotación de personal de serenazgo y como evitarlas, a efectos de que los funcionarios competentes del Corporativo Municipal puedan implementarlas para mitigar este fenómeno.Trabajo de investigaciónCampus Lima Centr
OSIRIS Software: The Mask Designer Tool
OSIRIS is a Day One instrument that will be available at the 10m GTC
telescope which is being built at La Palma observatory in the Canary Islands.
This optical instrument is designed to obtain wide-field narrow-band images
using tunable filters and to do low-resolution spectroscopy in both long-slit
and multislit modes. For the multislit spectroscopy mode, we have developed a
software to assist the observers to design focal plane masks. In this paper we
describe the characteristics of this Mask Designer tool. We discuss the main
design concepts, the functionality and particular features of the software.Comment: 6 figures; accepted for publication in Experimental Astronom
The lack of star formation gradients in galaxy groups up to z~1.6
In the local Universe, galaxy properties show a strong dependence on
environment. In cluster cores, early type galaxies dominate, whereas
star-forming galaxies are more and more common in the outskirts. At higher
redshifts and in somewhat less dense environments (e.g. galaxy groups), the
situation is less clear. One open issue is that of whether and how the star
formation rate (SFR) of galaxies in groups depends on the distance from the
centre of mass. To shed light on this topic, we have built a sample of X-ray
selected galaxy groups at 0<z<1.6 in various blank fields (ECDFS, COSMOS,
GOODS). We use a sample of spectroscopically confirmed group members with
stellar mass M >10^10.3 M_sun in order to have a high spectroscopic
completeness. As we use only spectroscopic redshifts, our results are not
affected by uncertainties due to projection effects. We use several SFR
indicators to link the star formation (SF) activity to the galaxy environment.
Taking advantage of the extremely deep mid-infrared Spitzer MIPS and
far-infrared Herschel PACS observations, we have an accurate, broad-band
measure of the SFR for the bulk of the star-forming galaxies. We use
multi-wavelength SED fitting techniques to estimate the stellar masses of all
objects and the SFR of the MIPS and PACS undetected galaxies. We analyse the
dependence of the SF activity, stellar mass and specific SFR on the
group-centric distance, up to z~1.6, for the first time. We do not find any
correlation between the mean SFR and group-centric distance at any redshift. We
do not observe any strong mass segregation either, in agreement with
predictions from simulations. Our results suggest that either groups have a
much smaller spread in accretion times with respect to the clusters and that
the relaxation time is longer than the group crossing time.Comment: Accepted for publication in MNRA
The OTELO survey: A case study of [O III] lambda 4959,5007 emitters at z=0.83
Context. The OSIRIS Tunable Filter Emission Line Object (OTELO) survey is a very deep, blind exploration of a selected region of the Extended Groth Strip and is designed for finding emission-line sources (ELSs). The survey design, observations, data reduction, astrometry, and photometry, as well as the correlation with ancillary data used to obtain a final catalogue, including photo-z estimates and a preliminary selection of ELS, were described in a previous contribution.
Aims. Here, we aim to determine the main properties and luminosity function (LF) of the [O III] ELS sample of OTELO as a scientific demonstration of its capabilities, advantages, and complementarity with respect to other surveys.
Methods. The selection and analysis procedures of ELS candidates obtained using tunable filter pseudo-spectra are described. We performed simulations in the parameter space of the survey to obtain emission-line detection probabilities. Relevant characteristics of [O III] emitters and the LF ([O III]), including the main selection biases and uncertainties, are presented.
Results. From 541 preliminary emission-line source candidates selected around z = 0.8, a total of 184 sources were confirmed as [O III] emitters. Consistent with simulations, the minimum detectable line flux and equivalent width in this ELS sample are ∼5 × 10−19 erg s−1 cm2 and ∼6 Å, respectively. We are able to constrain the faint-end slope (α = −1.03 ± 0.08) of the observed LF ([O III]) at a mean redshift of z = 0.83. This LF reaches values that are approximately ten times lower than those from other surveys. The vast majority (84%) of the morphologically classified [O III] ELSs are disc-like sources, and 87% of this sample is comprised of galaxies with stellar masses of M⋆ < 1010 M⊙
On Star Formation Rates and Star Formation Histories of Galaxies out to z ~ 3
We compare multi-wavelength SFR indicators out to z~3 in GOODS-South. Our
analysis uniquely combines U-to-8um photometry from FIREWORKS, MIPS 24um and
PACS 70, 100, and 160um photometry from the PEP survey, and Ha spectroscopy
from the SINS survey. We describe a set of conversions that lead to a
continuity across SFR indicators. A luminosity-independent conversion from 24um
to total infrared luminosity yields estimates of LIR that are in the median
consistent with the LIR derived from PACS photometry, albeit with significant
scatter. Dust correction methods perform well at low to intermediate levels of
star formation. They fail to recover the total amount of star formation in
systems with large SFR_IR/SFR_UV ratios, typically occuring at the highest SFRs
(SFR_UV+IR \gtrsim 100 Msun/yr) and redshifts (z \gtrsim 2.5) probed. Finally,
we confirm that Ha-based SFRs at 1.5<z<2.6 are consistent with SFR_SED and
SFR_UV+IR provided extra attenuation towards HII regions is taken into account
(Av,neb = Av,continuum / 0.44). With the cross-calibrated SFR indicators in
hand, we perform a consistency check on the star formation histories inferred
from SED modeling. We compare the observed SFR-M relations and mass functions
at a range of redshifts to equivalents that are computed by evolving lower
redshift galaxies backwards in time. We find evidence for underestimated
stellar ages when no stringent constraints on formation epoch are applied. We
demonstrate how resolved SED modeling, or alternatively deep UV data, may help
to overcome this bias. The age bias is most severe for galaxies with young
stellar populations, and reduces towards older systems. Finally, our analysis
suggests that SFHs typically vary on timescales that are long (at least several
100 Myr) compared to the galaxies' dynamical time.Comment: Accepted for publication in The Astrophysical Journal, 19 pages, 15
figure
La rotación de personal de serenazgo de la Subgerencia de Serenazgo de la Gerencia de Seguridad Ciudadana de la Municipalidad Distrital de Miraflores, dentro del Plan Estratégico Distrital de Seguridad Ciudadana del año 2018 como un indicador de gestión
Trabado de investigacionEl presente trabajo de investigación refiere a la rotación de personal de serenazgo de la Subgerencia de Serenazgo de la Gerencia de Seguridad Ciudadana de la Municipalidad Distrital de Miraflores dentro del Plan Estratégico Distrital de Seguridad Ciudadana del año 2018 como un indicador de gestión, siendo que dicha comuna tiene como domicilio fiscal sito en la Av. Larco N° 400, Miraflores - Lima.
Los resultados que se obtengan en el presente estudio nos permitirá conocer las posibles causas que da origen a este fenómeno, toda vez que viene afectando el cumplimiento del objetivo general del Plan Estratégico Distrital de Seguridad Ciudadana del 2018, que establece: “Fortalecer el trabajo multisectorial en el distrito mediante la interrelación, capacitación, asistencia técnica y administrativa de los sectores e instituciones comprometidas, con la participación de la comunidad organizada, a fin de mejorar los niveles de percepción de seguridad ciudadana”.
La hipótesis general del presente estudio señala que: “La insatisfacción en el trabajo percibido por el personal de serenazgo aumentará el índice de rotación del personal”; por lo que, a través de una contrastación, se obtendrá los resultados respectivos, y que en el contenido de las conclusiones y recomendaciones se pondrá de manifiesto las causas que originan la rotación de personal de serenazgo y como evitarlas, a efectos de que los funcionarios competentes del Corporativo Municipal puedan implementarlas para mitigar este fenómeno
COALAS : I. ATCA CO(1-0) survey and luminosity function in the Spiderweb protocluster at z=2.16
We report a detailed CO(1−0) survey of a galaxy protocluster field at z = 2.16, based on 475 h of observations with the Australia Telescope Compact Array. We constructed a large mosaic of 13 individual pointings, covering an area of 21 arcmin2 and ±6500 km s−1 range in velocity. We obtained a robust sample of 46 CO(1−0) detections spanning z = 2.09−2.22, constituting the largest sample of molecular gas measurements in protoclusters to date. The CO emitters show an overdensity at z = 2.12−2.21, suggesting a galaxy super-protocluster or a protocluster connected to large-scale filaments of ∼120 cMpc in size. We find that 90% of CO emitters have distances >0.5−4 to the center galaxy, indicating that small area surveys would miss the majority of gas reservoirs in similar structures. Half of the CO emitters have velocities larger than escape velocities, which appears gravitationally unbound to the cluster core. These unbound sources are barely found within the R200 radius around the center, which is consistent with a picture in which the cluster core is collapsed while outer regions are still in formation. Compared to other protoclusters, this structure contains a relatively higher number of CO emitters with relatively narrow line widths and high luminosities, indicating galaxy mergers. We used these CO emitters to place the first constraint on the CO luminosity function and molecular gas density in an overdense environment. The amplitude of the CO luminosity function is 1.6 ± 0.5 orders of magnitude higher than that observed for field galaxy samples at z ∼ 2, and one order of magnitude higher than predictions for galaxy protoclusters from semi-analytical SHARK models. We derive a high molecular gas density of 0.6−1.3 × 109 cMpc−3 for this structure, which is consistent with predictions for cold gas density of massive structures from hydro-dynamical DIANOGA simulations