Multiwavelength study of a young open cluster NGC 7419

Using new UBVRI H αCCD photometric observations and the archival infrared and X-ray data, we have carried out a multiwavelength study of a Perseus arm young open star cluster NGC 7419. An age of 22.5 ± 3.0 Myr and a distance of 3230+330-430 pc are derived for the cluster. Our photometric data indicate a higher value of colour excess ratio E(U-B)/E(B-V) than the normal one. There is an evidence for mass segregation in this dynamically relaxed cluster and in the range 1.4-8.6 M⊚, the mass function slope is in agreement with the Salpeter value. Excess emissions in near-infrared and H α support the existence of a young (≤ 2 Myr) stellar population of Herbig Ae/Be stars (≥3.0 M⊚) indicating a second episode of star formation in the cluster region. Using XMM-Newton observations, we found several X-ray sources in the cluster region but none of the Herbig Ae/Be stars is detected in X-rays. We compare the distribution of upper limits for Herbig Ae/Be stars with the X-ray distribution functions of the T Tauri and the Herbig Ae/Be stars from previous studies, and found that the X-ray emission level of these Herbig Ae/Be stars is not more than LX~ 5.2 × 1030 ergs-1, which is not significantly higher than for the T Tauri stars. Therefore, X-ray emission from Herbig Ae/Be stars could be the result of either unresolved companion stars or a process similar to T Tauri stars. We report an extended X-ray emission from the cluster region NGC 7419, with a total X-ray luminosity estimate of ~1.8 × 1031 erg s-1 arcmin-2. If the extended emission is due to unresolved emission from the point sources then we estimate ~288 T Tauri stars in the cluster region each having X-ray luminosity ~1.0 × 1030 ergs-1. Investigation of dust attenuation and 12CO emission map of a square degree region around the cluster indicates the presence of a foreground dust cloud which is most likely associated with the local arm star-forming region (Sh2-154). This cloud harbours uniformly distributed pre-main-sequence stars (0.1-2.0 M⊚ ), with no obvious trend of their distribution with either (H-K) excess or AV. This suggests that the star formation in this cloud depend mostly upon the primordial fragmentation

Raspberry-Pi and IoT based Health Monitoring System

The observation of the patient wirelessly could be a major improvement within the medical domain. The sensors once integrated into a wireless communication network, helps to remotely collect physiological signals of patient and avoid observation exploitation ancient medical instruments that makes the patient tether. During this paper, the observation of the patient is finished by the doctor endlessly while not really visiting the patient. Here, we tend to square measure exploitation varied sensors to sense the physiological parameters like temperature, vital sign, graphical record and therefore the level of saline. These detected signals square measure transmitted to the Raspberry pi to update the info endlessly via ADC which can convert these analog signals into digital signals. Through transmitter, the info is distributed wirelessly to the monitor screen of the doctor. So, the doctor will visualize the patient’s knowledge simply by sitting in his cabin. Once a important condition happens, the visual indications are going to be sent onto the screen

RJK Observations of the Optical Afterglow of GRB 991216

We present near-infrared and optical observations of the afterglow to the Gamma-Ray Burst (GRB) 991216 obtained with the F. L. Whipple Observatory 1.2-m telescope and the University of Hawaii 2.2-m telescope. The observations range from 15 hours to 3.8 days after the burst. The temporal behavior of the data is well described by a single power-law decay with index -1.36 +/-0.04, independent of wavelength. The optical spectral energy distribution, corrected for significant Galactic reddening of E(B-V)=0.626, is well fitted by a single power-law with index -0.58 +/- 0.08. Combining the IR/optical observations with a Chandra X-ray measurement gives a spectral index of -0.8 +/- 0.1 in the synchrotron cooling regime. A comparison between the spectral and temporal power-law indices suggest that a jet is a better match to the observations than a simple spherical shock.Comment: Accepted to the Astrophysical Journal, 12 pages, 4 postscript figure

Multi-wavelength study of a young open cluster NGC 7419

Using UBVRI Halpha CCD photometric observations and the archival NIR and X-ray data, we have carried out a multi-wavelength study of a young star cluster NGC 7419. An age of 22.5+/-3.0 Myr and a distance of 3230^{+330}_{-430} pc are derived for the cluster with a higher value of color excess ratio E(U-B)/E(B-V) than the normal one. There is an evidence for mass segregation in this dynamically relaxed cluster with mass function slope is in agreement with the Salpeter value. NIR and Halpha excess support the existence of a young (< 2 Myr) stellar population of Herbig Ae/Be stars (> 3.0 M_sun) indicating a second episode of star formation in the cluster region. Using XMM-Newton observations, we found several X-ray sources in the cluster region but none of the Herbig Ae/Be stars is detected in X-rays. We compare the distribution of upper limits for Herbig Ae/Be stars with the X-ray distribution functions of the T-Tauri and the Herbig Ae/Be stars from previous studies, and found that the X-ray emission level of these Herbig Ae/Be stars is not more than L_X ~5.2 x 10^{30} erg/s, which is not significantly higher than for the T-Tauri stars. Therefore, X-ray emission from Herbig Ae/Be stars could be the result of either unresolved companion stars or a process similar to T-Tauri stars. We report an extended X-ray emission from the cluster region NGC 7419, with a total L_X estimate of ~ 1.8 x 10^31 erg/s/arcmin^2. Investigation of dust and CO map of 1 degree region around the cluster indicates the presence of a foreground dust cloud which is most likely associated with star forming region Sh2-154. This cloud harbors uniformly distributed pre main sequence stars (0.1-2.0M_sun) and the star formation in this cloud depend mostly upon the primordial fragmentation.Comment: 23 pages, 23 figures, 13 tables; Accepted for publication in MNRA

Mass functions and photometric binaries in nine open clusters

Using homogeneous CCD photometric data from the 105-cm Kiso Schmidt telescope covering a 50' x 50' field, we study the mass functions (MFs) of nine open clusters. The ages and Galactocentric distances of the target clusters vary from 16 - 2000 Myr and 9-10.8 kpc, respectively. The values of MF slopes vary from -1.1 to -2.1. The classical value derived by Salpeter (1955) for the slope of the IMF is \Gamma = -1.35. The MFs in the outer regions of the clusters are found to be steeper than in the inner regions, indicating the presence of mass segregation in the clusters.The MF slopes (in the outer region as well as the whole cluster) undergo an exponential decay with the evolutionary parameter \tau (= age/ relaxation time). It seems that the evaporation of low-mass members from outer regions of the clusters is not significant at larger Galactocentric distances. It is concluded that the initial mass function (IMF) in the anticentre direction of the Galaxy might have been steeper than the IMF in the opposite direction. A comparison of the observed CMDs of the clusters with synthetic CMDs gives a photometric binary content of ~40%.Comment: Accepted for the publication in AJ, 21 Pages, 11 Figures, 9 Table

Star formation in young star cluster NGC 1893

We present a comprehensive multi-wavelength study of the star-forming region NGC 1893 to explore the effects of massive stars on low-mass star formation. Using near-infrared colours, slitless spectroscopy and narrow-band $H\alpha$ photometry in the cluster region we have identified candidate young stellar objects (YSOs) distributed in a pattern from the cluster to one of the nearby nebulae Sim 129. The $V, (V-I)$ colour-magnitude diagram of the YSOs indicates that majority of these objects have ages between 1 to 5 Myr. The spread in the ages of the YSOs may indicate a non-coeval star formation in the cluster. The slope of the KLF for the cluster is estimated to be $0.34\pm0.07$, which agrees well with the average value ($\sim 0.4$) reported for young clusters. For the entire observed mass range $0.6 < M/M_\odot \le 17.7$ the value of the slope of the initial mass function, $`\Gamma$', comes out to be $-1.27\pm0.08$, which is in agreement with the Salpeter value of -1.35 in the solar neighborhood. However, the value of $`\Gamma$' for PMS phase stars (mass range $0.6 < M/M_\odot \le 2.0$) is found to be $-0.88\pm0.09$ which is shallower than the value ($-1.71\pm0.20$) obtained for MS stars having mass range $2.5 < M/M_\odot \le 17.7$ indicating a break in the slope of the mass function at $\sim 2 M_\odot$. Estimated $`\Gamma$' values indicate an effect of mass segregation for main-sequence stars, in the sense that massive stars are preferentially located towards the cluster center. The estimated dynamical evolution time is found to be greater than the age of the cluster, therefore the observed mass segregation in the cluster may be the imprint of the star formation process. There is evidence for triggered star formation in the region, which seems to govern initial morphology of the cluster.Comment: Accepted for the publication in MNRAS, 21 pages, 26 figures, 10 table

Rapid UBVRI Follow-up of the Highly Collimated Optical Afterglow of GRB010222

(Abridged) We present the earliest optical observations of the optical counterpart to the GRB 010222, obtained with the FLWO 1.2-m telescope in UBVRI passbands, starting 3.64 hours after the burst. We also present late R-band observations of the afterglow obtained with the 1.8-m VATT ~25 days after the burst. The temporal analysis of our data joined with published data indicates a steepening decay, independent of wavelength, asymptotically approaching t^{-0.80+/-0.05} at early times (t << 1 day) and t^{-1.30+/-0.05} at late times, with a sharp break at t_b=0.72+/-0.1 days. This is the second earliest observed break of any afterglow (after GRB 980519), which clearly indicates the importance of rapid multi-band follow-up for GRB afterglow research. The optical spectral energy distribution, corrected for small Galactic reddening, can be fit fairly well by a single power-law with a slope of -1.07+/-0.09. However, when we fit using our BVRI data only, we obtain a shallower slope of -0.88+/- 0.1, in excellent agreement with the slope derived from our low-resolution spectrum (-0.89 +/- 0.03). The spectral slope and light curve decay slopes we derive are not consistent with a jet model despite the presence of a temporal break. Significant host dust extinction with a star-burst reddening law would flatten the spectral index to match jet predictions and still be consistent with the observed spectral energy distribution. We derive an opening angle of 2.1 deg, smaller than any listed in the recent compilation of Frail et al. The total beamed energy corrected for the jet geometry is 4x10^50 erg, very close to the ``standard'' value of 5x10^50 erg found by Frail et al. for a number of other bursts with light-curve breaks.Comment: revised version (minor changes only) to be published in the ApJ Part 1, 12 pages, 4 figures; all data used for the fits and our CCD frames available at ftp://cfa-ftp.harvard.edu/pub/kstanek/GRB010222/ and through WWW at http://cfa-www.harvard.edu/cfa/oir/Research/GRB