Low mass T Tauri and young brown dwarf candidates in the Chamaeleon II dark cloud found by DENIS

We define a sample designed to select low-mass T Tauri stars and young brown dwarfs using DENIS data in the Chamaeleon II molecular cloud. We use a star count method to construct an extinction map of the Chamaeleon II cloud. We select our low-mass T Tauri star and young brown dwarf candidates by their strong infrared colour excess in the I-J/J-K_s colour-colour dereddened diagram. We retain only objects with colours I-J>2, and spatially distributed in groups around the cloud cores. This provides a sample of 70 stars of which 4 are previously known T Tauri stars. We have carefully checked the reliability of all these objects by visual inspection on the DENIS images. Thanks to the association of the optical I-band to the infra-red J and K_s bands in DENIS, we can apply this selection method to all star formation regions observed in the southern hemisphere. We also identify six DENIS sources with X-ray sources detected by ROSAT. Assuming that they are reliable low-mass candidates and using the evolutionary models for low-mass stars, we estimate the age of these sources between 1 Myr and < 10 Myr.Comment: 7 Pages, including 3 PostScript figures. Accepted for publication in Astronomy & Astrophysic

UBVRI CCD photometric study of the open clusters Basel 4 and NGC 7067

In this paper we present UBVRI CCD photometry in the region of two young open star clusters Basel 4 and NGC 7067 for the first time. Our sample consists of ~ 4000 stars down to V ~ 21 mag. Stellar surface density profile indicates that radius of Basel 4 and NGC 7067 are about 1.8 and 3.0 arcmin respectively.The (U-B) versus (B-V) diagrams indicate that metallicity of NGC 7067 is solar while that of Basel 4 is Z ~ 0.008. We estimate the mean value of E(B-V) = 0.45$\pm$0.05 and 0.75$\pm$0.05 mag for Basel 4 and NGC 7067 respectively. The analysis of 2MASS JHK data in combination with the optical data in both the clusters yields E(J-K) = 0.30$\pm$0.20 mag and E(V-K) = 1.60$\pm$0.20 mag for Basel 4 while E(J-K) = 0.40$\pm$0.20 mag and E(V-K) = 2.10$\pm$0.20 mag for NGC 7067. Furthermore, colour excess diagrams show a normal interstellar extinction law towards both the clusters. Using the intrinsic colour-magnitude diagrams of the cluster members, we estimated the distances of the clusters as 3.0$\pm$0.2 and 3.6$\pm$0.2 Kpc for Basel 4 and NGC 7067 respectively. By fitting the proper metallicity isochrones to the bright cluster members we estimated the age of the clusters as 200$\pm$50 and 100$\pm$25 Myr for Basel 4 and NGC 7067 respectively. The mass function slope which is derived by applying the corrections of field star contamination and data incompleteness are $1.55\pm0.25$ and $1.68\pm0.47$ for Basel 4 and NGC 7067 respectively. The values of mass function slopes are thus not too different from the Salpeter's (1955) value. Mass segregation is observed in both the clusters which may be due to the dynamical evolutions or imprint of star formation processes or both.Comment: 14 pages, 12 figures, Accepted for publication in MNRA

A comprehensive CCD photometric study of the open cluster NGC 2421

We present the $UBVRI$ CCD photometry in the region of the open cluster NGC 2421. Radius of the cluster is determined as $\sim$ 3$^\prime$.0 using stellar density profile. Our Study indicates that metallicity of the cluster is $Z \sim$ 0.004. The reddening $E(B-V) = 0.42\pm$0.05 mag is determined using two colour $(U-B)$ versus $(B-V)$ diagram. By combining the 2MASS $JHK$ data with the optical data we determined $E(J-K) = 0.20\pm$0.20 mag and $E(V-K) = 1.15\pm$0.20 mag for this cluster. Colour-excess diagrams show normal interstellar extinction law in the direction of the cluster. We determined the distance of the cluster as 2.2$\pm$0.2 Kpc by comparing the ZAMS with the intrinsic CM diagram of the cluster. The age of the cluster has been estimated as 80$\pm$20 Myr using the stellar isochrones of metallicity $Z = 0.004$. The mass function slope $x = 1.2\pm0.3$ has been derived by applying the corrections of field stars contamination and data incompleteness. Our analysis indicate that the cluster NGC 2421 is dynamically relaxed.Comment: 10 pages, 13 figures, Accepted for publication in MNRA

The ideal of the certainty in law: the skin and the heart of law

The doubt about certainty like an absolute value in law and as an ideal full in legal system (argument about impossibility) is a controversial fact in contemporary legal theory. In this text I examine some contemporary doctrines about the classic understanding (in critical sense) of this ideal. I have selected the most representative doctrines: doctrine about "open texture of Law" (H.L.A. Hart), starting point in this discussion; doctrine about "Il Diritto mite" (G. Zagrebelsky), from the continental European legal tradition at present; and doctrine about "vagueness in Law" (T.A.O. Endicott), this doctrine is the most recent, from the Anglo-Saxon legal tradition. Finally, in Conclusions, I analyze if this doubt (argument about impossibility) contaminates (in some sense) to the concept of law or to the characteristics that describe law in the contemporary Constitutional State

Dust, Ice and Gas in Time (DIGIT) Herschel program first results: A full PACS-SED scan of the gas line emission in protostar DK Cha

DK Cha is an intermediate-mass star in transition from an embedded configuration to a star plus disk stage. We aim to study the composition and energetics of the circumstellar material during this pivotal stage. Using the Range Scan mode of PACS on the Herschel Space Observatory, we obtained a spectrum of DK Cha from 55 to 210 micron as part of the DIGIT Key Program. Almost 50 molecular and atomic lines were detected, many more than the 7 lines detected in ISO-LWS. Nearly the entire ladder of CO from J=14-13 to 38-37 (E_u/k = 4080 K), water from levels as excited as E_u/k = 843 K, and OH lines up to E_u/k = 290 K were detected. The continuum emission in our PACS SED scan matches the flux expected from a model consisting of a star, a surrounding disk of 0.03 Solar mass, and an envelope of a similar mass, supporting the suggestion that the object is emerging from its main accretion stage. Molecular, atomic, and ionic emission lines in the far-infrared reveal the outflow's influence on the envelope. The inferred hot gas can be photon-heated, but some emission could be due to C-shocks in the walls of the outflow cavity.Comment: 4 Page letter, To appear in A&A special issue on Hersche

Infrared study of the eta Chamaeleontis cluster and the longevity of circumstellar discs

We have analyzed JHKL observations of the stellar population of the ~9 Myr-old eta Chamaeleontis cluster. Using infrared (IR) colour-colour and colour-excess diagrams, we find the fraction of stellar systems with near-IR excess emission is 0.60 pm 0.13 (2_sigma). This results implies considerably longer disc lifetimes than found in some recent studies of other young stellar clusters. For the classical T Tauri (CTT) and weak-lined T Tauri (WTT) star population, we also find a strong correlation between the IR excess and H_alpha emission. The IR excesses of these stars indicate a wide range of star-disc activity; from a CTT star showing high levels of accretion, to CTT - WTT transition objects with evidence for some on-going accretion, and WTT stars with weak or absent IR excesses. Of the 15 known cluster members, 4 stars with IR excesses delta(K-L) > 0.4 mag are likely experiencing on-going accretion owing to strong or variable optical emission. The resulting accretion fraction (0.27 pm 0.13; 2_sigma) shows that the accretion phase, in addition to the discs themselves, can endure for at least ~10 Myr.Comment: 7 pages, 4 figures, accepted for MNRA

A deep UVBRI CCD photometric study of open clusters Tr 1 and Be 11

We present deep $UBVRI$ CCD photometry for the young open star clusters Tr 1 and Be 11. The CCD data for Be 11 is obtained for the first time. The sample consists of $\sim$ 1500 stars reaching down to $V$ $\sim$ 21 mag. Analysis of the radial distribution of stellar surface density indicates that radius values for Tr 1 and Be 11 are 2.3 and 1.5 pc respectively. The interstellar extinction across the face of the imaged clusters region seems to be non-uniform with a mean value of $E(B-V)$ = 0.60$\pm$0.05 and 0.95$\pm$0.05 mag for Tr 1 and Be 11 respectively. A random positional variation of $E(B-V)$ is present in both the clusters. In the cluster Be 11, the reason of random positional variation may be apparent association of the HII region (S 213). The 2MASS $JHK$ data in combination with the optical data in the cluster Be 11 yields $E(J-K)$ = 0.40$\pm$0.20 mag and $E(V-K)$ = 2.20$\pm$0.20 mag. Colour excess diagrams indicate a normal interstellar extinction law in the direction of cluster Be 11. The distances of Tr 1 and Be 11 are estimated as 2.6$\pm$0.10 and 2.2$\pm$0.10 Kpc respectively, while the theoretical stellar evolutionary isochrones fitted to the bright cluster members indicate that the cluster Tr 1 and Be 11 are 40$\pm$10 and 110$\pm$10 Myr old. The mass functions corrected for both field star contamination and data incompleteness are derived for both the clusters. The slopes $1.50\pm0.40$ and $1.22\pm0.24$ for Tr 1 and Be 11 respectively are in agreement with the Salpeter's value. Observed mass segregations in both clusters may be due to the result of dynamical evolutions or imprint of star formation processes or both.Comment: 15 pages, 13 figures. Accepted for publication in MNRA

Lithium abundances along the RGB: FLAMES-GIRAFFE spectra of a large sample of low-mass Bulge stars

Context: A small number of K-type giants on the red giant branch (RGB) is known to be very rich in lithium (Li). This fact is not accounted for by standard stellar evolution theory. The exact phase and mechanism of Li enrichment is still a matter of debate. Aims: Our goal is to probe the abundance of Li along the RGB, from its base to the tip, to confine Li-rich phases that are supposed to occur on the RGB. Methods: For this end, we obtained medium-resolution spectra with the FLAMES spectrograph at the VLT in GIRAFFE mode for a large sample of 401 low-mass RGB stars located in the Galactic bulge. The Li abundance was measured in the stars with a detectable Li 670.8 nm line by means of spectral synthesis with COMARCS model atmospheres. A new 2MASS (J-K) - Teff calibration from COMARCS models is presented in the Appendix. Results: Thirty-one stars with a detectable Li line were identified, three of which are Li-rich according to the usual criterion ($\log\epsilon({\rm Li})>1.5$). The stars are distributed all along the RGB, not concentrated in any particular phase of the red giant evolution (e.g. the luminosity bump or the red clump). The three Li-rich stars are clearly brighter than the luminosity bump and red clump, and do not show any signs of enhanced mass loss. Conclusions: We conclude that the Li enrichment mechanism cannot be restricted to a clearly defined phase of the RGB evolution of low-mass stars (M\sim1M_{\sun}), contrary to earlier suggestions from disk field stars.Comment: 6 pages (14 with appendix), 5 figures (1 in appendix), accepted for publication in A&

F. J. Gómez Espelosín, En busca de Alejandro: historia de una obsesión, Alcalá de Henares, Servicio de publicaciones de la UAH, 2016

Obra ressenyada: F. J. GÓMEZ ESPELOSÍN, En busca de Alejandro: historia de una obsesión. Alcalá de Henares: Universidad de Alcalá de Henares. Servicio de publicaciones, 2016

The restoration of the bell tower of Alcalà de Xivert (Spain): Significance and function

[EN] The text addresses the research and preliminary studies carried out on this outstanding bell tower, its precarious state of repair, the criteria adopted beforehand and the tasks performed during the restoration works, which involved the whole building, including the treatment of the stone. Of special interest is the consolidation of the upper part of the bell tower structure with the intervention on the sculpture of St John, which required a detailed study of its history and the vicissitudes it had undergone before proceeding to repair its anchorage and its lead sheet cladding.[ES] El texto presenta la investigación y los estudios previos desarrollados en torno a este importante y significativo campanario, su delicado estado de conservación que amenaza peligro, los criterios asumidos previamente y los trabajos desarrollados durante las obras de restauración, que han contemplado el conjunto del mismo, incluido el tratamiento de la piedra. Especialmente interesante es la consolidación de la parte superior de la estructura del campanario con la intervención de la escultura de San Juan, que implicó un estudio detallado de su historia y avatares, antes de la reparación de su anclaje y su revestimiento de láminas de plomo.Soler Verdú, R.; Soler Estrela, A. (2014). La recuperación de la torre campanario de Alcalà de Xivert (España): Signo y función. Loggia, Arquitectura & Restauración. (26):38-57. doi:10.4995/loggia.2013.3166385726ANÓNIMO/ANONYMOUS: "La torre campanario recuerdo del primer centenario (1803-1903)" en La Iglesia (1766/2003) y el campanario (1803/2003) de Alcalá de Xivert, Centre de Estudis del Maestrat, Benicarló, 2003, p 107-110.CUCALA LARROSA, E.: "Breve reseña histórica de la construcción del campanario de Alcalá de Chivert", en Varios apuntes. Obra inédita, Tomo III, p. 223.CUCALA LARROSA, E.: Rematant lo Campanar. Adaptación de Joan-V Sanz y Joaquim Arnau, 2005.BÉRCHEZ, J. y JARQUE, F.: Arquitectura barroca valenciana, Bancaja, Valencia, 1993.GIL SAURA, Y. Arquitectura barroca en Castellón, Diputación provincial de Castellón, 2004.GINER SOSPEDRA, V.: "La torre campanario de Alcalá de Xivert" en La Iglesia (1766/2003) y el campanario (1803/2003) de Alcalá de Xivert, Centre de Estudis del Maestrat, Benicarló, 2003. (Publicado en la revista Penyagolosa nº 9.1972), p. 111-122.ITURAT GARCÍA, J.: "Apoteosis barroca: La torre campanario" en La Iglesia (1766/2003) y el campanario (1803/2003) de Alcalá de Xivert, Centre de Estudis del Maestrat, Benicarló, 2003, p. 123-130.JUAN VIDAL, F.: Los campanarios de José Minguez. Valencia 1700-1750, TC Cuadernos, Valencia, 2000.MARTÍ, J.: "Campanario", en La Iglesia (1766/2003) y el campanario (1803/2003) de Alcalá de Xivert, Centre de Estudis del Maestrat, Benicarló, 2003 (Publicado en la revista II Centenario de la Iglesia parroquial, 1966), p. 133-137.SOLER, R.: "Propuesta de metodología de estudios previos a la restauración" en 24 lecciones sobre conservación del patrimonio arquitectónico. Su razón de ser, Universidad Politécnica de Valencia, 2012, p. 433-460.VARONA, J. E. et al.: El llibre de fàbrica del Campanar d'Alcalà, Associació d'Amics de Mainhardt, Alcalà de Xivert, 2009