Abstract
SN 2014C was originally classified as a Type Ib supernova, but at phase
ϕ
= 127 days, post-explosion strong H
α
emission was observed. SN 2014C has since been observed in radio, infrared, ...optical and X-ray bands. Here we present new optical spectroscopic and photometric data spanning
ϕ
= 947–2494 days post-explosion. We address the evolution of the broadened H
α
emission line, as well as broad O
iii
emission and other lines. We also conduct a parallel analysis of all publicly available multiwavelength data. From our spectra, we find a nearly constant H
α
FWHM velocity width of ∼2000 km s
−1
that is significantly lower than that of other broadened atomic transitions (∼3000–7000 km s
−1
) present in our spectra (O
i
λ
6300; O
iii
λ
λ
4959, 5007; He
i
λ
7065; Ca
ii
λ
λ
7291, 7324). The late radio data demand a fast forward shock (∼10,000 km s
−1
at
ϕ
= 1700 days) in rarified matter that contrasts with the modest velocity of the H
α
. We propose that the infrared flux originates from a toroidal-like structure of hydrogen surrounding the progenitor system, while later emission at other wavelengths (radio, X-ray) likely originates predominantly from the reverse shock in the ejecta and the forward shock in the quasi-spherical progenitor He-wind. We propose that the H
α
emission arises in the boundary layer between the ejecta and torus. We also consider the possible roles of a pulsar and a binary companion.
Einstein’s theory of general relativity was proposed over 100 years ago and has successfully passed a large number of observational tests in the weak field regime. However, the strong field regime is ...largely unexplored, and there are many modified and alternative theories that have the same predictions as Einstein’s gravity for weak fields and present deviations when gravity becomes strong. relxill_nk is the first relativistic reflection model for probing the spacetime metric in the vicinity of astrophysical black holes and testing Einstein’s gravity in the strong field regime. Here, we present our current constraints on possible deviations from Einstein’s gravity obtained from the black holes in 1H0707–495, Ark 564, GX 339–4, and GS 1354–645.
ABSTRACT
Ultrafast outflows (UFOs) have been revealed in a large number of active galactic nuclei (AGN) and are regarded as promising candidates for AGN feedback on the host galaxy. The nature and ...launching mechanism of UFOs are not yet fully understood. Here we perform a time- and flux-resolved X-ray spectroscopy on four XMM–Newton observations of a highly accreting narrow-line Seyfert 1 (NLS1) galaxy, Mrk 1044, to study the dependence of the outflow properties on the source luminosity. We find that the UFO in Mrk 1044 responds to the source variability quickly and its velocity increases with the X-ray flux, suggesting a high-density ($10^{9}\!-\!4.5\times 10^{12}\, \mathrm{cm}^{-3}$) and radiatively driven outflow, launched from the region within a distance of $98\!-\!6600\, R_\mathrm{g}$ from the black hole. The kinetic energy of the UFO is conservatively estimated ($L_\mathrm{UFO}\sim 4.4~{{\ \rm per\ cent}}\, L_\mathrm{Edd}$), reaching the theoretical criterion to affect the evolution of the host galaxy. We also find that emission lines, from a large-scale region, have a blueshift of 2700–4500 km s−1 in the spectra of Mrk 1044, which is rarely observed in AGN. By comparing with other sources, we propose a correlation between the blueshift of emission lines and the source accretion rate, which can be verified by a future sample study.
Context. Ultra-fast outflows (UFOs) have been revealed in a large number of active galactic nuclei (AGN) in the past two decades. Their extreme velocities and high ionization states make them a ...promising candidate for AGN feedback on the evolution of the host galaxy. However, their exact underlying driving mechanism is not yet fully understood. Aims. Given that the variability of UFOs may be used to distinguish among different launching mechanisms, we aim to search for and characterize the responses of the UFO properties to the variable irradiating luminosity. Methods. We perform a high-resolution time- and flux-resolved spectroscopy of archival XMM-Newton observations on six highly accreting narrow-line Seyfert 1 (NLS1) galaxies, selected by UFO detection and sufficient exposure times. The state-of-the-art methods of the blind Gaussian line scan and photoionization model scan are used to identify UFO solutions. We search for ionized winds and investigate the structure of ionized winds and their responses to the luminosity variations. The location, density, and kinetic energy of UFOs are estimated as well. Results. The powerful photoionization model scan reveals three previously unreported UFOs in RE J1034+396, PG 1244+026 and I ZW 1 with a detection significance above 3 σ , and two new warm absorbers (WAs) in RE J1034+396. Five out of six (83%) AGN in our sample host multi-phase ionized winds, where outflows in I ZW 1 are energy-conserved. The relatively low-ionization entrained UFOs are discovered in four (66%) AGN of our sample, supporting the shocked outflow interpretation for ionized winds in AGN. We notice that two out of seven (28%) UFOs in our sample seem to respond to the radiation field and three (43%) UFOs hint at a radiatively accelerated nature, requiring further observations. Combined with published works, we do not find any correlations between UFO responses and AGN properties except for a tentative (∼1.8 σ ) anti-correlation between the UFO acceleration and the Eddington ratio, to be confirmed by further observations and an enlarged sample. The kinetic energy of UFOs, mostly detected in soft X-rays, is found to have a large uncertainty. We, therefore, cannot conclude whether soft X-ray UFOs have sufficient energy to drive the AGN feedback, although they are very promising based on some reasonable assumptions. The primary UFO in I ZW 1 (detected in the hard X-ray) is the only case in our sample to possess conclusively sufficient energy to affect the host galaxy.
Bamboos, widely distributed in tropical and subtropical regions and significant in ecological, economic and cultural values, are similar to trees in the above-ground growth and to geophytes in the ...below-ground structure. However, contrary to well-studied endodormancy and the related chilling requirement that synchronize the seasonal development of above-ground buds of tree species and the well-studied below-ground buds of geophytes, it is unknown whether bamboos demonstrate the endodormancy and chilling requirements as those of trees and geophytes, which limits our understanding of how bamboos phenology cope with climate change. Our work mainly examined the effect of temperature on the dormancy release of underground shoot buds of two important subtropical running bamboo species, Lei bamboo (Phyllostachys violascens) and Moso bamboo (Phyllostachys edulis). In the experiments, the bamboo seedlings were first subjected to different durations of natural chilling and subsequently to a regrowth test under high-temperature forcing conditions in whole-tree chambers. In the regrowth test the dormancy state of the shoot buds was examined by observing shoot development, i.e., the emergence of the new shoot aboveground, a significant spring phenological event in many bamboo species. The time required for shooting under the forcing conditions decreased with prolonged chilling, indicating that the shoot buds of these two bamboo species demonstrate the phenomena of endodormancy and a chilling requirement for endodormancy release. For Lei bamboo, the chilling requirement was estimated as 45 Chill Portions (CP) and heat requirement was 9978 ± 6713 GDH℃. As for Moso bamboo, the estimated chilling requirement was 35CP and heat requirement was 6713 ± 3087 GDH℃. Meanwhile, the Vegis effect (an interaction of previous chilling accumulation and forcing temperature) was also found in Lei bamboo: there was a large difference in the time required for shoot development between low and high forcing temperatures after short durations of chilling, but the difference decreased with prolonged chilling. It was also shown that bamboo shoot buds almost received the same heat requirements for emergence at different forcing temperatures under the same chilling requirements. Our results will improve the understanding of temperature regulation of spring phenology in subtropical bamboo forests and promote bamboo production and management.
●Shoot buds of subtropical running bamboo have an endodormancy period.●Chilling requirement contributes to the release of endodormancy in shoot buds.●The shoot bud’s dormancy release depends on the interaction of chilling accumulation and forcing temperature.●This study possibly suggests that evergreens geophytes demonstrate both ecodormancy and endodormancy.
It is thought that the spacetime metric around astrophysical black holes is well described by the Kerr solution of Einstein's gravity. However, robust observational evidence of the Kerr nature of ...these objects is still lacking. Here we fit the X-ray spectrum of the stellar-mass black hole in GS 1354-645 with a disk reflection model beyond Einstein's gravity in order test the Kerr black hole hypothesis. We consider the Johannsen metric with the deformation parameters 13 and 22. The Kerr metric is recovered for . For 22 = 0, our measurements of the black hole spin and of the deformation parameter 13 are and −0.34 < 13 < 0.16, respectively. For 13 = 0, we find a* > 0.975 and −0.09 < 22 < 0.42. All the reported uncertainties are at 99% of confidence level for two relevant parameters.
Abstract
We present a detailed spectral analysis of the joint XMM-Newton and NuSTAR observations of the active galactic nuclei (AGNs) in the Seyfert 1.5 Galaxy ESO 362-G18. The broadband (0.3–79 keV) ...spectrum shows the presence of a power-law continuum with a soft excess below 2 keV, iron K
α
emission (∼6.4 keV), and a Compton hump (peaking at ∼20 keV). We find that the soft excess can be modeled by two different possible scenarios: a warm (
kT
e
∼ 0.2 keV) and optically thick (
τ
∼ 34) Comptonizing corona, or with a relativistically blurred reflection off a high-density (
) inner disk. These two models cannot be easily distinguished solely from their fit statistics. However, the low temperature (
kT
e
∼ 20 keV) and the thick optical depth (
τ
∼ 5) of the hot corona required by the warm corona scenario are uncommon for AGNs. We also fit a “hybrid” model, which includes both disk reflection and a warm corona. Unsurprisingly, as this is the most complex of the models considered, this provides the best fit, and more reasonable coronal parameters. In this case, the majority of the soft excess flux arises in the warm corona component. However, based on recent simulations of warm coronae, it is not clear whether such a structure can really exist at the low accretion rates relevant for ESO 362-G18 (
). This may therefore argue in favor of a scenario in which the soft excess is instead dominated by the relativistic reflection. Based on this model, we find that the data would require a compact hot corona (
h
∼ 3
R
Horizon
) around a rapidly spinning (
a
⋆
> 0.927) black hole.
The ataxia telangiectasia mutated and rad3-related (ATR) kinase regulates the DNA damage response (DDR), which plays a critical role in the ATR-Chk1 signaling pathway. ATR inhibition can induce ...synthetic lethality (SL) with several DDR deficiencies, making it an attractive drug target for cancers with DDR defects. In this study, we developed a series of selective and potent ATR inhibitors with a thieno3,2-dpyrimidine scaffold using a hybrid design. We identified compound 34 as a representative molecule that inhibited ATR kinase with an IC50 value of 1.5 nM and showed reduced potency against other kinases tested. Compound 34 also exhibited potent antiproliferative effects against LoVo cells and SL effects against HT-29 cells. Moreover, compound 34 demonstrated good pharmacokinetic properties, in vivo antitumor efficacy, and no obvious toxicity in the LoVo xenograft tumor model. Therefore, compound 34 is a promising lead compound for drug development to combat specific DDR deficiencies in cancer patients.
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•SAR study of thieno3,2-dpyrimidine-based ATR inhibitors was performed.•34 potently suppressed ATR and induced synthetic lethality in vitro.•34 displayed high target selectivity over the 80 screened kinases.•34 exhibited good PK properties and antitumor activityin vivo.
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•Pyrido3,2-dpyrimidine derivatives were designed and synthesized as new ATR inhibitors.•10q exhibited potent activity against ATR in both biochemical and cellular assays.•10q ...exhibited good metabolic stability in different species of liver microsomes.•Combination treatment of 10q and AZD1390 in HT-29 cells confirmed synthetic lethality between ATR and ATM.
Targeting ataxia telangiectasia mutated and Rad3-related (ATR) kinase is being pursued as a new therapeutic strategy for the treatment of advanced solid tumor with specific DNA damage response deficiency. Herein, we report a series of pyrido3,2-dpyrimidine derivatives with potent ATR inhibitory activity through structure-based drug design. Among them, the representative compound 10q exhibited excellent potency against ATR in both biochemical and cellular assays. More importantly, 10q exhibited good liver microsomes stability in different species and also showed moderate inhibitory activity against HT-29 cells in combination treatment with the ATM inhibitor AZD1390. Thus, this work provides a promising lead compound against ATR for further study.
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