115,249 research outputs found
Spectral analysis of the Chandra comet survey
No full textAims.We present results of the analysis of cometary X-ray spectra with an extended version of our charge exchange emission model (Bodewits et al. 2006). We have applied this model to the sample of 8 comets thus far observed with the Chandra X-ray observatory and ACIS spectrometer in the 300-1000 eV range. The surveyed comets are C/1999 S4 (LINEAR), C/1999 T1 (McNaught-Hartley), C/2000 WM1 (LINEAR), 153P/2002 (Ikeya-Zhang), 2P/2003 (Encke), C/2001 Q4 (NEAT), 9P/2005 (Tempel 1) and 73P/2006-B (Schwassmann-Wachmann 3) and the observations include a broad variety of comets, solar wind environments and observational conditions. Methods.The interaction model is based on state selective, velocity dependent charge exchange cross sections and is used to explore how cometary X-ray emission depend on cometary, observational and solar wind characteristics. It is further demonstrated that cometary X-ray spectra mainly reflect the state of the local solar wind. The current sample of Chandra observations was fit using the constrains of the charge exchange model, and relative solar wind abundances were derived from the X-ray spectra. Results.Our analysis showed that spectral differences can be ascribed to different solar wind states, as such identifying comets interacting with (I) fast, cold wind, (II), slow, warm wind and (III) disturbed, fast, hot winds associated with interplanetary coronal mass ejections. We furthermore predict the existence of a fourth spectral class, associated with the cool, fast high latitude wind
A star-forming galaxy at z= 5.78 in the Chandra Deep Field South
No full textWe report the discovery of a luminous z = 5.78 star-forming galaxy in the Chandra Deep Field South. This galaxy was selected as an ‘i-drop’ from the GOODS public survey imaging with the Hubble Space Telescope/Advanced Camera for Surveys (object 3 in the work of Stanway, Bunker & McMahon 2003). The large colour of (i′−z′)AB = 1.6 indicated a spectral break consistent with the Lyman α forest absorption shortward of Lyman α at z≈ 6. The galaxy is very compact (marginally resolved with ACS with a half-light radius of 0.08 arcsec, so rhl 5. Our spectroscopic redshift for this object confirms the validity of the i′-drop technique of Stanway et al. to select star-forming galaxies atz≈ 6
Radio sources in the Chandra Galactic Bulge Survey
No full textWe discuss radio sources in the Chandra Galactic Bulge Survey region. By cross-matching the X-ray sources in this field with the NRAO VLA Sky Survey archival data, we find 12 candidate matches. We present a classification scheme for radio/X-ray matches in surveys taken in or near the Galactic plane, taking into account other multiwavelength data. We show that none of the matches found here is likely to be due to coronal activity from normal stars because the radio to X-ray flux ratios are systematically too high. We show that one of the source could be a radio pulsar, and that one could be a planetary nebula, but that the bulk of the sources are likely to be background active galactic nuclei (AGN), with many confirmed through a variety of approaches. Several of the AGN are bright enough in the near-infrared (and presumably in the optical) to use as probes of the interstellar medium in the inner Galaxy
MIROC4-ACTM CO2 Inversion flux (2001-2022)
No full text<p>This dataset is prepared for GCP CO2-2023 assessment. </p>
<p>Inversion Details are in:</p>
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<div>Chandra, N., Patra, P. K., Niwa, Y., Ito, A., Iida, Y., Goto, D., Morimoto, S., Kondo, M., Takigawa, M., Hajima, T., and Watanabe, M.: Estimated regional CO<sub>2</sub> flux and uncertainty based on an ensemble of atmospheric CO<sub>2</sub> inversions, Atmos. Chem. Phys., 22, 9215–9243, https://doi.org/10.5194/acp-22-9215-2022, 2022</div>
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<div>MIROC4-ACTM Details:</div>
<div><span>Patra, P. K., Takigawa, M., Watanabe, S., Chandra, N., Ishijima, K., and Yamashita, Y.: Improved Chemical Tracer Simulation by MIROC4.0-based Atmospheric Chemistry-Transport Model (MIROC4-ACTM), SOLA, 14, 91–96, <a href="https://doi.org/10.2151/sola.2018-016">https://doi.org/10.2151/sola.2018-016</a>, 2018. </span></div>
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Penguin Classics
No full textFirst published in India in 1993, this is a very attractive Panchatantra. It is the first I know of that has been translated by a woman. I would like to make it my text the next time I go through the poem. For now I note that it is a full version, stretching over 435 pages before the notes. By contrast Olivelle's version in similar format finishes its text on 159. The introduction here is extensive and intelligent. Wily and Wary serve very well as names for Dimna and Kalila. The T of C at the beginning is detailed in its presentation of individual stories. The notes at the end are simple and pleasantly terse.Original language: sanFirst Great Britain/USA printingTranslated from the Sanskrit with an introduction by Chandra Raja
A remark on rational Cherednik algebras and differential operators on the cyclic quiver
No full textWe show that the spherical subalgebra Uk,c of the rational Cherednik algebra associated to Sn 2 Cl, the wreath product of the symmetric group and the cyclic group of order l, is isomorphic to a quotient of the ring of invariant differential operators on a space of representations of the cyclic quiver of size l. This confirms a version of [5, Conjecture 11.22] in the case of cyclic groups. The proof is a straightforward application of work of Oblomkov [12] on the deformed Harish–Chandra homomorphism, and of Crawley–Boevey, [3] and [4], and Gan and Ginzburg [7] on preprojective algebras
Penguin Classics
No full textThis is a "rejacketed" Penguin Classic, whose interior is entirely identical with that in the copy which this collection has from 1995. The final page of this copy tells "The Story of Penguin Classics," including the rejacketing of Penguin Classics in the 21st century. As I wrote of that earlier copy, this very attractive Panchatantra was first published in India in 1993. It is the first I know of that has been translated by a woman. I would like to make it my text the next time I go through the poem. For now I note that it is a full version, stretching over 435 pages before the notes. By contrast Olivelle's version in similar format finishes its text on 159. The introduction here is extensive and intelligent. "Wily" and "Wary" serve very well as names for Dimna and Kalila. The T of C at the beginning is detailed in its presentation of individual stories. The notes at the end are simple and pleasantly terse.Translated from the Sanskrit with an introduction by Chandra Raja
Chandra and RXTE spectroscopy of the accreting msec pulsar IGR J00291+5934
No full textWe report on an observation of the recently discovered accreting millisecond X-ray pulsar IGR J00291+5934 performed with the RXTE-Proportional Counter Array (PCA) and Chandra-High Energy Transmission Grating Spectrometer (HETGS). The RXTE data are from a twoweek follow-up of the source, while the Chandra observation took place around the end of the follow-up, about 12 days after the discovery of
the source, when the source flux had decreased already by a factor of ten. The analysis of the Chandra data allowed us to extract the most precise X-ray position of IGR J00291+5934, RA = 00h 29m 03.08s, and Dec =+59◦ 34 19.2 (0.6 error), compatible with the optical and radio ones.
We find that the spectra of IGR J00291+5934 can be described by a combination of a thermal component and a power-law. Along the outburst detected by PCA, the power-law photon index showed no particular trend, while the thermal component (∼1 keV, interpreted as a hot spot on
the neutron star surface) became weaker until non-detection. In the simultaneous observation of the weak Chandra /RXTE spectrum, there was no longer any indication of the ∼1 keV thermal component, while we detected a colder thermal component (∼0.4 keV) that we interpret as the
emission from the cold disc. A hint of a 6.4 keV iron line was detected, together with an excess around 6.8 keV and absorption feature around 7.1 keV. The last two features have never been detected in the spectra of accretion-driven millisecond pulsars before and, if confirmed, would
suggest the presence of an expanding hot corona with high outflow velocities
Letter, [Author unclear] to Paulina T. Merritt
No full textHandwritten letter to Paulina Merritt from an unknown author, October 1, 1876.
Tropiorhynchus annandalei Gupta & Chandra 2017, new species
No full text<i>Tropiorhynchus annandalei</i> Gupta & Chandra, new species <p>(Figs. 4–5, 9, 13, 17, 21, 31–33, 36, 40, 44, 48, 52, 53)</p> <p> <b>Type locality.</b> India, Maharashtra state, Pune district, Bhimashankar Wildlife Sanctuary, 19.1319°N, 73.5538°E.</p> <p> <b>Type material (7 specimens).</b> Holotype, male: “ India, Maharashtra state, Pune district, Bhimashankar Wildlife Sanctuary, 19.1319°N, 73.5538°E, 1.xi.2012, collected by K. Chandra and Bulganin Mitra ” (ZSCI registration number: 22708/H4A). Paratypes (5 males, 1 female): same data as holotype (ZSCI registration number: 22709/H4A to 22714/H4A). The specimens bear a red printed label: “ <i>Tropiorhynchus annandalei</i> sp. nov., HOLOTYPUS [or PARATYPUS], Devanshu Gupta & Kailash Chandra det. 2016”.</p> <p> <b>Type depository.</b> All the type specimens are deposited in the collection of Zoological Survey of India, Kolkata (ZSCI).</p> <p> <b>Description</b> (holotype, male). <b>Size.</b> Length from clypeus to pygidium: 12.0 mm, width across humeri: 5.4 mm.</p> <p> <b>Shape.</b> Elongate and parallel sided.</p> <p> <b>Colour.</b> Head, pronotum, and legs green; pygidium greenish black; elytra yellow with brownish-black markings, elytral suture entirely black. Elytral intervals 1 and 2 with a transverse band in middle and at end, elytral interval 3 brownish black with small yellow area in middle and at base, elytral interval 4 dark brownish black with a yellow strip present after interval 4; lateral sides entirely brownish black; setae white.</p> <p> <b>Head</b> (Fig. 9). Surface densely rugose, anterior portion smooth. Clypeus at apex rounded, at mid-disc with longitudinal ridge, not reaching to frontoclypeal suture. Frontoclypeal suture slightly curved in middle; frons rugopunctate, punctures fine at posterior portion; a group of white setae arising near margin of eyes.</p> <p> <b>Pronotum</b> (Fig. 13). Surface finely punctate; punctures saucer shaped, fine, not densely packed; edges of punctures near anterior portion not merged. Surface near base medially smooth; anterior angles pointed, posterior angles rounded, lateral sides rounded, side at base weakly sinuate. Posterior margin beaded, bead vanishing medially; a group of setae present at anterior angle, in middle and at posterior angle.</p> <p> <b>Elytra</b> (Fig. 17). Striae punctate; intervals convex and smooth, intervals 1 and 2 broad; stria 1 reaching to posterior margin, other striae vanishing before reaching posterior margin.</p> <p> <b>Scutellum</b> (Fig. 17). Traingular, broad at tip, surface finely punctate.</p> <p> <b>Pygidium (</b> Fig. 21). Strongly arched and convex, medially smooth, laterally rugose.</p> <p> <b>Venter.</b> Surface densely setose, setae white; mesosternum not produced.</p> <p> <b>Legs</b> (Figs. 31–33, 36, 40, 44). Protibiae bidentate, tibial teeth near apex. Longer claw of protarsi and mesotarsi spilt apically (Figs. 36, 40); metatarsal claws simple (Fig. 44); meso- and metatrochanter with sharp tooth (Figs. 32, 33); tooth on protrochanter absent (Fig. 31).</p> <p> <b>Aedeagus</b> (Figs. 48, 52). Parameres nearly straight (in lateral view); apex of parameres blunt, and markedly separated (in frontal view) (Fig. 48); ventral plate nearly straight without a raised lamina in middle; apex of ventral plate without a hooked process (Fig. 52).</p> <p> <b>Female (paratype)</b> (Fig. 53). Differs from male in elytra rather broad, surface yellow, comparatively lessdeveloped elytral markings, legs comparatively short, metafemora broad, metatrochanter with less-developed spines.</p> <p> <b>Collecting circumstances.</b> Handpicked from grasses (Fig. 53).</p> <p> <b>Distribution:</b> Only known from type locality (Fig. 5).</p> <p> <b>Etymology.</b> The species is named in the honor of Dr. Thomas Nelson Annandale, founder Director of Zoological Survey of India, Kolkata.</p> <p> <b>Differential diagnosis.</b> <i>Tropiorhynchus annandalei</i> is distinguished by the unique structure of aedeagus, elytral markings, medially smooth and laterally rugose pygidial surface, and tooth on protrochanter nearly absent.</p> <p> The new species belongs to the genus <i>Tropiorhynchus</i> based on the following set of diagnostic characters: clypeus produced into a truncate rostrum; pronotum broadly transverse, more-or-less setose; pygidium convex; protibiae bidentate, teeth sharp; mesotibiae and metatibiae narrowing slightly towards apex, scarcely spinose; tarsal claws long, slender, and unequal; mesosternum not produced beyond mesocoxae.</p> <p> The new species is similar to <i>T</i>. <i>podagricus</i> and <i>T</i>. <i>umbrinus</i> as it has a clypeus with a longitudinal ridge in middle; pronotum with setae present only near anterior margin, anterior angles acute, posterior angles blunt, lateral side at posterior margin straight; and mesosternum not produced.</p> <p> The new species is the only species in the genus in which the ventral plate of the aedeagus is nearly straight and without a hooked process at tip (Fig. 52). The other species of the genus exhibit a ventral plate with a hooked tip (Figs. 49–51). Furthermore, <i>T. orientis</i> exhibits an anteriorly straight ventral plate with a raised lamina in middle and tip with a small pointed hook (Fig. 49). As discussed by Machatschke (1954), the ventral plate in <i>T</i>. <i>podagricus</i> is strongly curved with its tips pointed (Fig. 50) whereas in <i>T</i>. <i>umbrinus</i>, the ventral plate is filamentous, slightly curved with the tip strongly pointed and beak shaped (Fig. 51). See Table 1 for the identification of <i>T. annandalei</i>, <i>T. orientis</i>, <i>T</i>. <i>podagricus</i>, and <i>T</i>. <i>umbrinus</i>.</p>Published as part of <i>Gupta, Devanshu & Chandra, Kailash, 2017, Tropiorhynchus annandalei (Coleoptera: Scarabaeidae: Rutelinae), a new species from Maharashtra, India, pp. 509-522 in Zootaxa 4337 (4)</i> on pages 510-512, DOI: 10.11646/zootaxa.4337.4.3, <a href="http://zenodo.org/record/1034252">http://zenodo.org/record/1034252</a>
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