Optical-NIR analysis of globular clusters in the IKN dwarf spheroidal: a complex star formation history

Age, metallicity and spatial distribution of globular clusters (GCs) provide a powerful tool to reconstruct major star-formation episodes in galaxies. IKN is a faint dwarf spheroidal (dSph) in the M81 group of galaxies. It contains five old GCs, which makes it the galaxy with the highest known specific frequency (SN=126). We estimate the photometric age, metallicity and spatial distribution of the poorly studied IKN GCs. We search SDSS for GC candidates beyond the HST field of view, which covers half of IKN. To break the age-metallicity degeneracy in the V-I colour we use WHT/LIRIS Ks-band photometry and derive photometric ages and metallicities by comparison with SSP models in the V,I,Ks colour space. IKN GCs' VIKs colours are consistent with old ages ($\geq\!8$ Gyr) and a metallicity distribution with a higher mean than typical for such a dSph ([Fe/H$]\!\simeq\!-1.4_{-0.2}^{+0.6}$ dex). Their photometric masses range ($0.5 <{\cal M_{\rm GC}}<4\times10^5M_\odot$) implies a high mass ratio between GCs and field stars, of $10.6\%$. Mixture model analysis of the RGB field stars' metallicity suggests that 72\% of the stars may have formed together with the GCs. Using the most massive GC-SFR relation we calculate a SFR of $\sim\!10M_\odot/$yr during its formation epoch. We note that the more massive GCs are closer to the galaxy photometric centre. IKN GCs also appear spatially aligned along a line close to the IKN major-axis and nearly orthogonal to the plane of spatial distribution of galaxies in the M81 group. We identify one new IKN GC candidate based on colour and PSF analysis of the SDSS data. The evidence towards i) broad and high metallicity distribution of the field IKN RGB stars and its GCs, ii) high fraction and iii), spatial alignment of IKN GCs, supports a scenario for tidally triggered complex IKN's SFH in the context of interactions with galaxies in the M81 group.Comment: 12 pages, 9 figures, accepted to A&

High resolution imaging of the early-type galaxy NGC 1380: an insight into the nature of extended extragalactic star clusters

NGC 1380 is a lenticular galaxy located near the centre of the Fornax Cluster northeast of NGC 1399. The globular cluster system of this galaxy was previously studied only from the ground. Recent studies of similar early-type galaxies, specially lenticular ones, reveal the existence of star clusters that apparently break up the traditional open/globular cluster dichotomy. With higher quality photometry from HST/WFPC2 we study the star clusters in NGC 1380, measuring their magnitudes, colours, sizes and projected distances from the centre of the galaxy. We used deep archival HST/WFPC2 in the B and V bands. We built colour magnitude diagrams from which we selected a sample of cluster candidates. We also analysed their colour distribution and measured their sizes. Based on their location in the luminosity-size diagram we estimated probabilities of them being typical globular clusters as those found in the Galaxy. A total of about 570 cluster candidates were found down to V=26.5. We measured sizes for approximately 200 of them. The observed colour distribution has three apparent peaks. Likewise for the size distribution. We identified the smaller population as being mainly typical globular clusters, while the more extended objects have small probabilities of being such objects. Different correlations between absolute magnitudes, sizes, colours and location were inferred for these cluster sub-populations. Most extended clusters (Reff > 4 pc) share similar properties to the diffuse star clusters reported to inhabit luminous early-type galaxies in the Virgo galaxy cluster such as being of low surface brightness and fainter than MV ~ -8. We also report on a small group of (Reff ~ 10 pc), -8< MV < -6, red clusters located near the centre of NGC 1380, which may be interpreted as faint fuzzies.Comment: accepted for publication in A&

Lifting the dust veil from the Globular Cluster Palomar2

This work employs high-quality {\em Hubble Space Telescope} ({\em HST}) Advanced Camera for Surveys (ACS) F606W and F814W photometry to correct for the differential reddening affecting the colour-magnitude diagram (CMD) of the poorly-studied globular cluster (GC) Palomar\,2. Differential reddening is taken into account by assuming that morphological differences among CMDs extracted across the field of view of Palomar\,2 correspond essentially to shifts (quantified in terms of $\delta E(B-V)$) along the reddening vector due to a non-uniform dust distribution. The average reddening difference over all partial CMDs is $\overline{\delta E(B-V)}=0.24\pm0.08$, with the highest reaching $\delta E(B-V) =0.52$. The corrected CMD displays well-defined and relatively narrow evolutionary sequences, especially for the evolved stars, i.e. the red-giant, horizontal and asymptotic giant branches (RGB, HB and AGB, respectively). The average width of the upper main sequence and RGB profiles of the corrected CMD corresponds to 56\% of the original one. Parameters measured on this CMD show that Palomar\,2 is $\approx13.25$\,Gyr old, has the mass $M\sim1.4\times10^5\,m_\odot$ stored in stars, is affected by the foreground $E(B-V)\approx0.93$, is located at $d_\odot\approx26$\,Kpc from the Sun, and is characterized by the global metallicity $Z/Zo\approx0.03$, which corresponds to the range $-1.9\leq [Fe/H] \leq-1.6$ (for $0.0\leq[\alpha/Fe]\leq+0.4$), quite consistent with other outer halo GCs. Additional parameters are the absolute magnitude $M_V\approx-7.8$, and the core and half-light radii $r_C\approx2.6$\,pc and $R_{HL}\approx4.7$\,pc, respectively.Comment: Accepted for publication by MNRA

Lifting the dust veil from the globular cluster Palomar 2

This work employs high-quality Hubble Space Telescope (HST) Advanced Camera for Surveys (ACS) F606W and F814W photometry to correct for the differential reddening affecting the colour–magnitude diagram (CMD) of the poorly studied globular cluster (GC) Palomar 2. Differential reddening is taken into account by assuming that morphological differences among CMDs extracted across the field of view of Palomar 2 correspond essentially to shifts (quantified in terms of δE(B − V)) along the reddening vector due to a non-uniform dust distribution. The average reddening difference over all partial CMDs is δE(B−V)=0.24±0.08, with the highest reaching δE(B − V) = 0.52. The corrected CMD displays well-defined and relatively narrow evolutionary sequences, especially for the evolved stars, i.e. the red giant, horizontal, and asymptotic giant branches (RGB, HB, and AGB, respectively). The average width of the upper main sequence and RGB profiles of the corrected CMD corresponds to 56 per cent of the original one. Parameters measured on this CMD show that Palomar 2 is ≈13.25 Gyr old, has the mass M∼1.4×105M⊙ stored in stars, is affected by the foreground E(B − V) ≈ 0.93, is located at d⊙ ≈ 26 kpc from the Sun, and is characterized by the global metallicity Z/Z⊙ ≈ 0.03, which corresponds to the range −1.9 ≤ [Fe/H] ≤ −1.6 (for 0.0 ≤ [α/Fe] ≤ +0.4), quite consistent with other outer halo GCs. Additional parameters are the absolute magnitude MV ≈ −7.8, and the core and half-light radii rC ≈ 2.6 pc and RHL ≈ 4.7 pc, respectively

Burocracia, sociedad civil e ideología en América Latina

Public servants are conditioned by perceptions about their jobs environments that can lead them to have less appreciation for their organizations. There are few studies that focus on a theoretical and practical understanding of the organizational environment as a factor that may lead public workers to low motivation and job satisfaction levels. We aim to explore organizational environment of Colombia’s public-sector entities as a key organizational aspect, considering the demographic characteristics of Colombian public servants. Through multivariate statistics we explore whether some demographic and organizational traits of public officials play a role on their appreciations of their organizational environments. To do so, we use data from a survey of the National Department of Statistics of Colombia, covering more than 6,000 public officials at the regional level. This article aims to inform practice since it provides empirical evidence about Colombia’s public organizations employees, suggesting that graduate middle professionals with more than six years of service, and technicians with more than twelve years of service tend to purport negative perceptions about the organizational environments of Colombian public organizations. Thus, seniority in Colombia appears to have a key role on such perceptions.El trabajo de los servidores públicos está condicionado por sus percepciones acerca del ambiente de trabajo, las cuales pueden llevarlos a afectar sus visiones sobre la organización. No existen muchos estudios que, a nivel teórico o práctico, analicen en Colombia el ambiente laboral como un factor relacionado con la motivación y la satisfacción laboral de los servidores públicos. A través del uso de técnicas estadísticas multivariadas, este artículo explora si: diferentes factores sociodemográficos y organizacionales tienen un efecto sobre las percepciones de los servidores acerca del ambiente laboral. Utilizamos datos del DANE, cubriendo más de 6,000 oficiales públicos a nivel regional

Bureaucracy, Civil Society and Ideology in Latin America

This essay analyzes how political and ideological changes affect public bureaucracy and its relationship with civil society regarding different strategies of openness to participation. We suggest a theoretical-conceptual framework to discuss aspects of the political situation in Latin America. First, we discuss the changes that occurred over time, in the state-civil society relationship, which strengthen the latter and amplify a discourse for more participatory democracy. The focus is the role of the public bureaucracy in mediating the relations among the several actors in society, and we examine the way different political and ideological strands influence how open to participation the bureaucracy is in different periods. The literature review indicates two trends in the state-civil society relationship: technocrat and popular. These reflect the two main ideologies affecting the behavior of public bureaucrats when it comes to participation. We argue that in Latin America, although there is a swing around two different old-fashioned ideologies, both of them reinforce the centrality of the state and its bureaucracy. Therefore, dominant ideologies are not helpful in responding to the need for a deeper state-society re-articulation, which indicates the need and the possibility of building a new ideological approach

The miniJPAS survey : white dwarf science with 56 optical filters

Aims. We analyze the white dwarf population in miniJPAS, the first square degree observed with 56 medium-band, 145 Å in width optical filters by the Javalambre Physics of the accelerating Universe Astrophysical Survey (J-PAS), to provide a data-based forecast for the white dwarf science with low-resolution (R ∼ 50) photo-spectra. Methods. We define the sample of the bluest point-like sources in miniJPAS with r 7000 K can be segregated from the bluest extragalactic QSOs, providing a clean sample based on optical photometry alone. Conclusions. The J-PAS low-resolution photo-spectra would produce precise effective temperatures and atmospheric compositions for white dwarfs, complementing the data from Gaia. J-PAS will also detect and characterize new white dwarfs beyond the Gaia magnitude limit, providing faint candidates for spectroscopic follow-up

An environmental dependence of the physical and structural properties in the Hydra cluster galaxies

The nearby Hydra cluster (∼50 Mpc) is an ideal laboratory to understand, in detail, the influence of the environment on the morphology and quenching of galaxies in dense environments. We study the Hydra cluster galaxies in the inner regions (1R200) of the cluster using data from the Southern Photometric Local Universe Survey, which uses 12 narrow and broad-band filters in the visible region of the spectrum. We analyse structural (Sérsic index, effective radius) and physical (colours, stellar masses, and star formation rates) properties. Based on this analysis, we find that ∼88 per cent of the Hydra cluster galaxies are quenched. Using the Dressler–Schectman test approach, we also find that the cluster shows possible substructures. Our analysis of the phase-space diagram together with density-based spatial clustering algorithm indicates that Hydra shows an additional substructure that appears to be in front of the cluster centre, which is still falling into it. Our results, thus, suggest that the Hydra cluster might not be relaxed. We analyse the median Sérsic index as a function of wavelength and find that for red [(u − r) ≥2.3] and early-type galaxies it displays a slight increase towards redder filters (13 and 18 per cent, for red and early type, respectively), whereas for blue + green [(u − r)<2.3] galaxies it remains constant. Late-type galaxies show a small decrease of the median Sérsic index towards redder filters. Also, the Sérsic index of galaxies, and thus their structural properties, do not significantly vary as a function of clustercentric distance and density within the cluster; and this is the case regardless of the filter

J-PLUS: a wide-field multi-band study of the M 15 globular cluster : evidence of multiple stellar populations in the RGB

Context. As a consequence of internal and external dynamical processes, Galactic globular clusters (GCs) have properties that vary radially. Wide-field observations covering the entire projected area of GCs out to their tidal radii (rtidal) can therefore give crucial information on these important relics of the Milky Way formation era. Aims. The Javalambre Photometric Local Universe Survey (J-PLUS) provides wide field-of-view (2 deg2) images in 12 narrow, intermediate and broad-band filters optimized for stellar photometry. Here we have applied J-PLUS data for the first time for the study of Galactic GCs using science verification data obtained for the very metal-poor ([Fe/H] ≈−2.3) GC M 15 located at ~10 kpc from the Sun. Previous studies based on spectroscopy found evidence of multiple stellar populations (MPs) through their different abundances of C, N, O, and Na. Our J-PLUS data provide low-resolution spectral energy distributions covering the near-UV to the near-IR, allowing us to instead search for MPs based on pseudo-spectral fitting diagnostics. Methods. We have built and discussed the stellar radial density profile (RDP) and surface brightness profiles (SBPs) reaching up to rtidal. Since J-PLUS FoV is larger than M 15’s rtidal, the field contamination can be properly taken into account. We also demonstrated the power of J-PLUS unique filter system by showing colour-magnitude diagrams (CMDs) using different filter combinations and for different cluster regions. Results. J-PLUS photometric quality and depth are good enough to reach the upper end of M 15’s main-sequence. CMDs based on the colours (u − z) and (J0378 − J0861) are found to be particularly useful to search for splits in the sequences formed by the upper red giant branch (RGB) and asymptotic giant branch (AGB) stars. We interpret these split sequences as evidence for the presence of MPs. Furthermore, we show that the (u − z) × (J0378 − g) colour–colour diagram allows us to distinguish clearly between field and M 15 stars, which is important to minimize the sample contamination. Conclusions. The J-PLUS filter combinations (u − z) and (J0378 − J0861), which are sensitive to metal abundances, are able to distinguish different sequences in the upper RGB and AGB regions of the CMD of M 15, showing the feasibility of identifying MPs without the need of spectroscopy. This demonstrates that the J-PLUS survey will have sufficient spatial coverage and spectral resolution to perform a large statistical study of GCs through multi-band photometry in the coming years