The central parsec of NGC 3783: a rotating broad emission line region, asymmetric hot dust structure, and compact coronal line region

Using VLTI/GRAVITY and SINFONI data, we investigate the subparsec gas and dust structure around the nearby type 1 active galactic nucleus (AGN) hosted by NGC 3783. The K-band coverage of GRAVITY uniquely allows simultaneous analysis of the size and kinematics of the broad line region (BLR), the size and structure of the near-infrared(near-IR)-continuum-emitting hot dust, and the size of the coronal line region (CLR). We find the BLR, probed through broad Brγ emission, to be well described by a rotating, thick disc with a radial distribution of clouds peaking in the inner region. In our BLR model, the physical mean radius of 16 light-days is nearly twice the ten-day time-lag that would be measured, which closely matches the ten-day time-lag that has been measured by reverberation mapping. We measure a hot dust full-width at half-maximum (FWHM) size of 0.74 mas (0.14 pc) and further reconstruct an image of the hot dust, which reveals a faint (5% of the total flux) offset cloud that we interpret as an accreting or outflowing cloud heated by the central AGN. Finally, we directly measure the FWHM size of the nuclear CLR as traced by the [Ca VIII] and narrow Brγ line. We find a FWHM size of 2.2 mas (0.4 pc), fully in line with the expectation of the CLR located between the BLR and narrow line region. Combining all of these measurements together with larger scale near-IR integral field unit and mid-IR interferometry data, we are able to comprehensively map the structure and dynamics of gas and dust from 0.01 to 100 pc.

Dust Structure Around Asymptotic Giant Branch Stars – CORRIGENDUM

The above article previously published with incorrect author information for Dr Binil Aryal. Dr Aryal’s affiliation should be listed as Central Department of Physics, Tribhuvan University, Kathmandu, Nepal. This error has since been rectified in the online PDF and HTML copies of the article.

Пылевая плазма в сильно неоднородном магнитном поле

The paper presents for the first time studies of dusty plasmas formed in a glow discharge in a region of a strongly inhomogeneous magnetic field. The inhomogeneity of the magnetic field is estimated as 0.2 T/cm. A steady dust trap has been detected. The geometric characteristics of the plasma-dust structure were determined; the angular velocity of rotation was measured in several sections perpendicular to the axis of the discharge tube. The mechanism of rotation of the plasma-dust structure is proposed, quantitative estimates are made that confirm the experimental data.

Dust Structure around AGB Star in 60μm and 100 μm IRAS Survey at Latitude 16.10°

A systematic search in the range of J2000 coordinate system provided by K.W. Shu & Y.J. Kwon (2011) of dust structure in the far infrared (100 μm and 60 μm) IRAS (Infrared Astronomical Satellite) survey was performed using Sky View virtual Observatory (1) so that some interesting isolated cavity structures surrounding the cavity structure were expected. The FITS images downloaded from sky view (1) was processed using software Aladin v 2.5. A cavity like structure (major diameter ∼ 3.57 pc & minor diameter ∼ 1.19 pc) lies in the coordinate of R.A. (J2000) 06h 31m 05s and DEC (J2000) 16d 06m 00s was found at the distance ∼ 310 pc (5). We studied the flux density variation and the temperature variation about major diameter, minor diameter and the distance between minimum temperature and minimum flux within the structure. We observed the variation of the temperature is 20.53 K to 21.42 K, with the offset of about 0.89 K, which shows the cavity is independently evolved. The mass profile of each pixel of the structure was also calculated using these temperature.The Himalayan Physics Vol. 6 & 7, April 2017 (48-53)

Dust Structure around two Asymptotic Giant Stars at Latitude 32° & 40.67°

We studied the dust structures in 60μm and 100μm infrared image around the two asymptotic giant branch (AGB) stars. A systematic search of dust structure in the far infrared (100 μm and 60 μm) Infrared Astronomical Satellite (IRAS) survey was performed using Sky View Observatory. In order to find the possible candidate of cavity structure not yet studied, we used SIMBAD database to locate discrete sources in the region. A new relatively symmetric spherical cavity like structure (size: 1.354 pc × 0.971 pc) for candidate I and (size: 1.424 pc × 0.925pc) for candidate II at R.A.(J2000) =04h46m13.84s, Dec.(J2000) = +32°31’39.6’’ and 05h05m59.58s; +40°40’33.4’’ respectively was found at the distance of about 280 pc and 390 pc. In this present work we have calculated the dust color temperature, mass, outflow velocity, energy and size. We also studied the flux density variation and then calculated temperature and mass profile of the dust and outflow nature of AGB wind using data reduction software’s Aladin v2.5 and Aladinv8.0. Our aim was to test how outflow can be seen in this region. We have studied two cavity-like structures. The dust color temperature is found to lie in the range 21.7 K to 35.6 K for candidate I and 18.5 K to 19.3 K, with an offset of about 14 K and 0.8 K respectively. An offset of 14 K suggests that the AGB is hot in early AGB phase now in late AGB stage. We expect deviation from symmetrical outflow, i.e., AGB wind probably prefer polytropic behaviour implies bipolar type wind whereas the offset 0.8 K for candidate II suggests that the AGB is in the symmetric AGB phase, i.e., early AGB stage. The total mass of the dust in the cavity structure is found about 5.93×1025 Kg (0.00003Mʘ) for candidate I and 1.95×1027Kg (0.001 Mʘ) for candidate II. In addition we have calculated outflow energy of C-rich AGB star along ISM using outflow velocity of our candidates. It is found that the outflow velocities are 12.96 ms-1 and 10.71 ms-1 respectively. For this we have calculated the value of speed of sound (Cs) and escape velocity (uesc). In this way we have determined outflow energy, i.e., 1.173×1025J and 2.766 × 1027J respectively.The Himalayan Physics Vol. 6 & 7, April 2017 (41-47)

A STUDY OF A PULSAR WIND DRIVEN STRUCTURE IN FAR-INFRARED IRAS MAP AT LATTITUDE -10º

A systematic search of dust structure in the far infrared (100 μm and 60 μm) IRAS (Infrared Astronomical Satellite) survey was performed using Sky View Observatory. In order to find the possible candidate, we used SIMBAD database to locate discrete sources in the region. A deep cavity-like isolated far infrared dust structure (size ~ 4.46 pc × 2.23 pc) at galactic longitude: 284.360o, galactic latitude: -9.549o was found at the distance of about 375 pc. We have studied the flux density variation and then calculated temperature and mass profile of the dust and excess mass using data reduction software ALADIN 7.5 within this region. The dust color temperature was found to lie in the range 23.40 K to 29.28 K. An offset temperature of about 6.0 K was found. The total mass of the dust structure was found to be about 2.55×1027 kg and the excess mass per pixel was 2.52×1024 kg. We also studied the rate of mass loading around the structure. The energy of the pulsar required to create that in homogeneity in the structure was calculated to be 5.04×1036 J. Possible explanations of results will be presented.Journal of Institute of Science and Technology, 2017, 22 (1): 1-9

A Study of Dust Structure around AGB Star in 60 and 100 μm IRAS Survey at Latitude 54.68º

<p class="Default">We have studied about the evolution of Asymptotic Giant Branch (AGB) stars, mass losses from them and a systematic search of AGB stars in J2000 coordinate system provided by K. W. Shu &amp; Y. J. Kwon (2011) of dust structure in the far infrared range (100 μm and 60 μm). For dust structure IRAS survey was performed using Sky View virtual Observatory. The FITS images downloaded from sky view was processed using software Aladin v 2.5. A cavity like structure (major diameter∼1.93 pc &amp; minor diameter∼ 0.89 pc) lies in the coordinate of R. A. (J2000) 04h 15m 03s and DEC (J2000) 54d 41m 00s was found at the distance∼ 240 pc. We studied the flux density variation and the temperature variation about major diameter, minor diameter and the distance between minimum temperature and minimum flux within the structure. We observed the variation of the temperature is 20.53 K to 21.09 K, with the offset of about 0.56 K, which show the cavity is independently evolved. The mass profile of each pixel of the structure was also calculated using this temperature.</p><p><strong>Journal of Nepal Physical Society</strong><em><br /></em>Volume 4, Issue 1, February 2017, Page: 67-77</p>