A photometric study of the old open clusters Berkeley 73, Berkeley 75 and Berkeley 25

CCD BVI photometry of the faint open clusters Berkeley 73, Berkeley 75 and Berkeley 25 are presented. The two latter are previously unstudied clusters to our knowledge. While Berkeley 73 is found to be of intermediate-age (about 1.5 Gyr old), Berkeley 75 and Berkeley 25 are old clusters, with ages greater than 3.0 Gyr. We provide also estimates of the clusters size. All these clusters lie far away from the Galactic Center, at R GC ≥ 16 kpc, and quite high on the Galactic plane, at |Z ⊙ | ≥ 1.5 kpc. They are therefore important targets to probe the properties of the structure of the Galaxy in this direction, where the Canis Major over-density has been discovered to be located.Facultad de Ciencias Astronómicas y Geofísica

The intermediate-age open clusters Ruprecht 61, Czernik 32, NGC 2225 and 2262

We present the first BVI CCD photometry to V = 22.0 of four fields centred on the region of the southern Galactic star clusters Ruprecht 61, Czernik 32, NGC 2225 and 2262 and of four displaced control fields. These clusters have never been studied before, and we provide for the first time estimates of their fundamental parameters, specifically radial extent, age, distance and reddening. We find that the four clusters are all of intermediate age (around 1 Gyr), close to the Sun and possess lower than solar metal abundance.Facultad de Ciencias Astronómicas y GeofísicasInstituto de Astrofísica de La Plat

NGC 2580 and NGC 2588 : Two open clusters in the Third Galactic Quadrant

We present CCD broad band photometric observations in the fields of the Third Galactic Quadrant open clusters NGC 2580 and NGC 2588 (V(I)C and UBV(RI)C respectively). From the analysis of our data we found that NGC 2580 is located at a distance of about 4 kpc and its age is close to 160 Myr. As for NGC 2588, it is placed at about 5 kpc from the Sun and is 450 Myr old. This means that NGC 2588 belongs to the extension of the Perseus arm, whereas NGC 2580 is closer to the local arm structure. The luminosity functions (LFs) have been constructed for both clusters down to V ∼ 20 together with their initial mass functions (IMFs) for stars with masses above M ∼ 1-1.5 M⊙. The IMF slopes for the most massive bins yielded values of x ≈ 1.3 for NGC 2580 and x ≈ 2 for NGC 2588. In the case of this latter cluster we found evidence of a core-corona structure produced probably by dynamical effect. In the main sequences of both clusters we detected gaps, which we suggest could be real features.Facultad de Ciencias Astronómicas y Geofísica

Demo: Real-time remote reporting of active regions with Wi-FLIP

This paper describes a real-time application programmed into Wi-FLIP, a wireless smart camera resulting from the integration of FLIP-Q, a focal-plane low-power image processor, and Imote2, a commercial WSN platform. The application, though simple, shows the potentiality of the reduced scene representations achievable at FLIP-Q to speed up the processing. It consists of detecting the active regions within the scene being surveyed, that is, those regions undergoing thresholded variations with respect to the background. If an activity pattern is prescribed, FLIP-Q enables the reconfigurability of the image plane accordingly, making its detection and tracking easier. For each frame, the number of active regions is calculated and wirelessly reported in real time. A base station picks up the radio signal and sends the information to a PC via USB, also in real time. Frame rates up to around 10fps have been achieved, although it greatly depends on the light conditions and the image plane division grid.Junta de Andalucía 2006-TIC-2352Ministerio de Ciencia TEC 2009-11812Office of Naval Research (USA) N00014111031

NGC 2401: A template of the young population of the Norma-Cygnus arm in the Third Galactic Quadrant

Based on a deep optical CCD [UBV(RI)C] photometric survey and on the Two-Micron All Sky Survey (2MASS) data, we derived the main parameters of the open cluster NGC 2401. We found that this cluster is placed at 6.3 ± 0.5 kpc (Vo - Mv = 14.0 ± 0.2) from the Sun and is 25 Myr old, which allows us to identify NGC 2401 as a member of the young population belonging to the innermost side of the extension of the Norma-Cygnus spiral arm in the Third Galactic Quadrant. A spectroscopic study of the emission star LSS 440 that lies in the cluster area revealed that it is a B0Ve star; however, we could not confirm that it is a cluster member. We also constructed the cluster luminosity function (LF) down to V ∼ 22 and the cluster initial mass function (IMF) for all stars with masses above M ∼ 1-2 M ⊙. It was found that the slope of the cluster IMF is x ≈ 1.8 ± 0.2. The presence of a probable pre-main-sequence (PMS) star population associated with the cluster is weakly revealed.Facultad de Ciencias Astronómicas y GeofísicasInstituto de Astrofísica de La Plat

Revisiting the area of the open cluster Stock 16

Deep CCD UBV(RI)C photometry has been carried out in the area of the open cluster Stock 16. The different photometric diagrams indicate the presence of three superimposed stellar groups, all composed of early type stars. The first of them, the cluster Stock 16, suffers from slightly variable reddening with a mean color excess 〈EB-V〉 = 0.51. The second group, reddened by 〈EB-V〉 = 0.84, includes the Wolf-Rayet star WR50 (a WC7+OB), and the third one, with a mean 〈E B-V〉 = 1.18, also includes another Wolf-Rayet star, WR 51 (a WN4+OB?). Our results confirm the distance and reddening already stated for Stock 16 but include new members. Concerning the other two highly reddened groups, we show that the first one - located at a distance of 3600 pc - is probably related to an anonymous OB association behind Cen OB1 also at 3600 pc already mentioned in the literature; the other seems to be a distant OB association - at more than 9000 pc - which may belong to the Scutum-Crux spiral arm. In these two groups we find evidence that the absorption law, A V/EB-V = R amounts to 4.0 approximately. The ages of the different star populations in the zone range from 5 × 106 yr to 6.4 × 106 yr for Stock 16, 8 × 106 for the second most reddened group and 5 × 106 for the probable association in Scutum-Crux. A determination of the IMF slope of Stock 16 was also carried out for stars in the mass range 1.8 < M < 14 M ⊙, giving a normal value x = 1.3.Este documento tiene una corrección (ver documento relacionado).Facultad de Ciencias Astronómicas y GeofísicasInstituto de Astrofísica de La Plat

Revisiting the area of the open cluster Stock 16

Deep CCD UBV(RI)C photometry has been carried out in the area of the open cluster Stock 16. The different photometric diagrams indicate the presence of three superimposed stellar groups, all composed of early type stars. The first of them, the cluster Stock 16, suffers from slightly variable reddening with a mean color excess 〈EB-V〉 = 0.51. The second group, reddened by 〈EB-V〉 = 0.84, includes the Wolf-Rayet star WR50 (a WC7+OB), and the third one, with a mean 〈E B-V〉 = 1.18, also includes another Wolf-Rayet star, WR 51 (a WN4+OB?). Our results confirm the distance and reddening already stated for Stock 16 but include new members. Concerning the other two highly reddened groups, we show that the first one - located at a distance of 3600 pc - is probably related to an anonymous OB association behind Cen OB1 also at 3600 pc already mentioned in the literature; the other seems to be a distant OB association - at more than 9000 pc - which may belong to the Scutum-Crux spiral arm. In these two groups we find evidence that the absorption law, A V/EB-V = R amounts to 4.0 approximately. The ages of the different star populations in the zone range from 5 × 106 yr to 6.4 × 106 yr for Stock 16, 8 × 106 for the second most reddened group and 5 × 106 for the probable association in Scutum-Crux. A determination of the IMF slope of Stock 16 was also carried out for stars in the mass range 1.8 < M < 14 M ⊙, giving a normal value x = 1.3.Este documento tiene una corrección (ver documento relacionado).Facultad de Ciencias Astronómicas y GeofísicasInstituto de Astrofísica de La Plat

Pesticide evaluation in water, sediment and in oyster shells (Crassostrea rhizophorae) in the Manzanillo- Niquero coastal area, Cuba

Occasionally pesticides have been used excessively for the pest control in agriculture, and many of these compounds become toxic for living organisms, including man. Adjacent lands to Guacanayabo gulf, Cuba, show an important use in agriculture, mainly in rice due to the contribution of fluvial waters from several hydrographical basins. The coastal area from Manzanillo to Niquero, Granma province, is the habitat of commercial shrimps, oysters and fish. The objective of the study was to determine in that region the presence of chemical residues from pesticides in the waters, sediments and shells of the mangrove oyster Crassostrea rhizophorae, Guilding (1828), as indicators of contamination. Samplings were carried out in maximum rainfall months. Besides samples for pesticide determination by gas chromatography, hydrology was studied, and there were carried out surveys (85 farmers) to know about pesticide types, dose and application frequency per crop, for conceptual analysis of the study objective. Results indicate a non-affectation by chemical residues of pesticides in any of the evaluated matrixes; and satisfactory quality of the waters for fishing use according to the used hydrological indicators. Ignorance exists on the farmer part on the application and dose of these chemical products, and recommendations are offered on pesticide use to prevent future impacts on the ecosystems