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At least 271 records · Page 15
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on HC6 by Materials Project

C6H crystallizes in the triclinic P-1 space group. The structure is one-dimensional and consists of one C6H ribbon oriented in the (1, 0, 0) direction. there are six inequivalent C+0.17- sites. In the first C+0.17- site, C+0.17- is bonded in a trigonal planar geometry to three C+0.17- atoms. There are a spread of C–C bond distances ranging from 1.40–1.44 Å. In the second C+0.17- site, C+0.17- is bonded in a trigonal planar geometry to three C+0.17- atoms. There are a spread of C–C bond distances ranging from 1.42–1.44 Å. In the third C+0.17- site, C+0.17- is bonded in a trigonal planar geometry to three C+0.17- atoms. There is two shorter (1.42 Å) and one longer (1.43 Å) C–C bond length. In the fourth C+0.17- site, C+0.17- is bonded in a distorted single-bond geometry to two equivalent C+0.17- and one H1+ atom. The C–H bond length is 1.09 Å. In the fifth C+0.17- site, C+0.17- is bonded in a trigonal planar geometry to three C+0.17- atoms. In the sixth C+0.17- site, C+0.17- is bonded in a trigonal planar geometry to three C+0.17- atoms. H1+ is bonded in a single-bond geometry to one C+0.17- atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on H2C3 by Materials Project

C3H2 crystallizes in the monoclinic C2/c space group. The structure is zero-dimensional and consists of four 2,3-dimethyl-1,3-butadiene molecules. there are three inequivalent C+0.67- sites. In the first C+0.67- site, C+0.67- is bonded in a distorted single-bond geometry to one C+0.67- and one H1+ atom. The C–C bond length is 1.41 Å. The C–H bond length is 1.09 Å. In the second C+0.67- site, C+0.67- is bonded in a distorted single-bond geometry to one C+0.67- and one H1+ atom. The C–C bond length is 1.41 Å. The C–H bond length is 1.09 Å. In the third C+0.67- site, C+0.67- is bonded in a trigonal planar geometry to three C+0.67- atoms. The C–C bond length is 1.48 Å. H1+ is bonded in a single-bond geometry to one C+0.67- atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on H4C by Materials Project

CH4 is Silicon tetrafluoride structured and crystallizes in the cubic I-43m space group. The structure is zero-dimensional and consists of two methane molecules. C4- is bonded in a tetrahedral geometry to four equivalent H1+ atoms. All C–H bond lengths are 1.10 Å. H1+ is bonded in a single-bond geometry to one C4- atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on H4C7 by Materials Project

C7H4 crystallizes in the monoclinic P2_1 space group. The structure is zero-dimensional and consists of two 1,1'-(1,8-naphthylene)bispyrene molecules. there are forty-two inequivalent C+0.57- sites. In the first C+0.57- site, C+0.57- is bonded in a distorted single-bond geometry to two C+0.57- and one H1+ atom. There is one shorter (1.37 Å) and one longer (1.44 Å) C–C bond length. The C–H bond length is 1.09 Å. In the second C+0.57- site, C+0.57- is bonded in a trigonal planar geometry to three C+0.57- atoms. There is one shorter (1.42 Å) and one longer (1.44 Å) C–C bond length. In the third C+0.57- site, C+0.57- is bonded in a trigonal planar geometry to three C+0.57- atoms. There are a spread of C–C bond distances ranging from 1.39–1.50 Å. In the fourth C+0.57- site, C+0.57- is bonded in a distorted single-bond geometry to one C+0.57- and one H1+ atom. The C–H bond length is 1.09 Å. In the fifth C+0.57- site, C+0.57- is bonded in a distorted single-bond geometry to one C+0.57- and one H1+ atom. The C–C bond length is 1.37 Å. The C–H bond length is 1.09 Å. In the sixth C+0.57- site, C+0.57- is bonded in a distorted trigonal planar geometry to two C+0.57- and one H1+ atom. The C–C bond length is 1.42 Å. The C–H bond length is 1.09 Å. In the seventh C+0.57- site, C+0.57- is bonded in a trigonal planar geometry to three C+0.57- atoms. There is one shorter (1.42 Å) and one longer (1.45 Å) C–C bond length. In the eighth C+0.57- site, C+0.57- is bonded in a distorted trigonal planar geometry to two C+0.57- and one H1+ atom. The C–C bond length is 1.37 Å. The C–H bond length is 1.09 Å. In the ninth C+0.57- site, C+0.57- is bonded in a distorted trigonal planar geometry to two C+0.57- and one H1+ atom. The C–C bond length is 1.41 Å. The C–H bond length is 1.09 Å. In the tenth C+0.57- site, C+0.57- is bonded in a distorted trigonal planar geometry to two C+0.57- and one H1+ atom. The C–C bond length is 1.39 Å. The C–H bond length is 1.09 Å. In the eleventh C+0.57- site, C+0.57- is bonded in a trigonal planar geometry to three C+0.57- atoms. There is one shorter (1.45 Å) and one longer (1.50 Å) C–C bond length. In the twelfth C+0.57- site, C+0.57- is bonded in a trigonal planar geometry to three C+0.57- atoms. In the thirteenth C+0.57- site, C+0.57- is bonded in a trigonal planar geometry to three C+0.57- atoms. There is one shorter (1.40 Å) and one longer (1.42 Å) C–C bond length. In the fourteenth C+0.57- site, C+0.57- is bonded in a distorted single-bond geometry to one C+0.57- and one H1+ atom. The C–H bond length is 1.09 Å. In the fifteenth C+0.57- site, C+0.57- is bonded in a distorted single-bond geometry to one C+0.57- and one H1+ atom. The C–C bond length is 1.40 Å. The C–H bond length is 1.09 Å. In the sixteenth C+0.57- site, C+0.57- is bonded in a trigonal planar geometry to three C+0.57- atoms. There is one shorter (1.43 Å) and one longer (1.44 Å) C–C bond length. In the seventeenth C+0.57- site, C+0.57- is bonded in a trigonal planar geometry to three C+0.57- atoms. There is one shorter (1.43 Å) and one longer (1.44 Å) C–C bond length. In the eighteenth C+0.57- site, C+0.57- is bonded in a distorted single-bond geometry to one C+0.57- and one H1+ atom. The C–H bond length is 1.09 Å. In the nineteenth C+0.57- site, C+0.57- is bonded in a distorted single-bond geometry to one C+0.57- and one H1+ atom. The C–C bond length is 1.43 Å. The C–H bond length is 1.09 Å. In the twentieth C+0.57- site, C+0.57- is bonded in a trigonal planar geometry to three C+0.57- atoms. There is one shorter (1.41 Å) and one longer (1.43 Å) C–C bond length. In the twenty-first C+0.57- site, C+0.57- is bonded in a trigonal planar geometry to three C+0.57- atoms. The C–C bond length is 1.43 Å. In the twenty-second C+0.57- site, C+0.57- is bonded in a distorted trigonal planar geometry to two C+0.57- and one H1+ atom. The C–C bond length is 1.40 Å. The C–H bond length is 1.09 Å. In the twenty-third C+0.57- site, C+0.57- is bonded in a distorted single-bond geometry to one C+0.57- and one H1+ atom. The C–H bond length is 1.09 Å. In the twenty-fourth C+0.57- site, C+0.57- is bonded in a distorted single-bond geometry to one C+0.57- and one H1+ atom. The C–C bond length is 1.41 Å. The C–H bond length is 1.09 Å. In the twenty-fifth C+0.57- site, C+0.57- is bonded in a trigonal planar geometry to three C+0.57- atoms. The C–C bond length is 1.43 Å. In the twenty-sixth C+0.57- site, C+0.57- is bonded in a distorted single-bond geometry to one C+0.57- and one H1+ atom. The C–H bond length is 1.09 Å. In the twenty-seventh C+0.57- site, C+0.57- is bonded in a distorted single-bond geometry to one C+0.57- and one H1+ atom. The C–C bond length is 1.44 Å. The C–H bond length is 1.09 Å. In the twenty-eighth C+0.57- site, C+0.57- is bonded in a trigonal planar geometry to three C+0.57- atoms. In the twenty-ninth C+0.57- site, C+0.57- is bonded in a trigonal planar geometry to three C+0.57- atoms. The C–C bond length is 1.40 Å. In the thirtieth C+0.57- site, C+0.57- is bonded in a distorted single-bond geometry to two C+0.57- and one H1+ atom. The C–C bond length is 1.39 Å. The C–H bond length is 1.09 Å. In the thirty-first C+0.57- site, C+0.57- is bonded in a distorted trigonal planar geometry to two C+0.57- and one H1+ atom. The C–C bond length is 1.40 Å. The C–H bond length is 1.09 Å. In the thirty-second C+0.57- site, C+0.57- is bonded in a trigonal planar geometry to three C+0.57- atoms. Both C–C bond lengths are 1.43 Å. In the thirty-third C+0.57- site, C+0.57- is bonded in a trigonal planar geometry to three C+0.57- atoms. The C–C bond length is 1.43 Å. In the thirty-fourth C+0.57- site, C+0.57- is bonded in a distorted single-bond geometry to two C+0.57- and one H1+ atom. The C–C bond length is 1.37 Å. The C–H bond length is 1.09 Å. In the thirty-fifth C+0.57- site, C+0.57- is bonded in a distorted trigonal planar geometry to two C+0.57- and one H1+ atom. The C–C bond length is 1.43 Å. The C–H bond length is 1.09 Å. In the thirty-sixth C+0.57- site, C+0.57- is bonded in a trigonal planar geometry to three C+0.57- atoms. There is one shorter (1.41 Å) and one longer (1.43 Å) C–C bond length. In the thirty-seventh C+0.57- site, C+0.57- is bonded in a trigonal planar geometry to three C+0.57- atoms. The C–C bond length is 1.43 Å. In the thirty-eighth C+0.57- site, C+0.57- is bonded in a distorted trigonal planar geometry to two C+0.57- and one H1+ atom. The C–C bond length is 1.40 Å. The C–H bond length is 1.09 Å. In the thirty-ninth C+0.57- site, C+0.57- is bonded in a distorted single-bond geometry to one C+0.57- and one H1+ atom. The C–H bond length is 1.09 Å. In the fortieth C+0.57- site, C+0.57- is bonded in a distorted single-bond geometry to one C+0.57- and one H1+ atom. The C–C bond length is 1.41 Å. The C–H bond length is 1.09 Å. In the forty-first C+0.57- site, C+0.57- is bonded in a trigonal planar geometry to three C+0.57- atoms. The C–C bond length is 1.43 Å. In the forty-second C+0.57- site, C+0.57- is bonded in a distorted trigonal planar geometry to two C+0.57- and one H1+ atom. The C–H bond length is 1.09 Å. There are twenty-four inequivalent H1+ sites. In the first H1+ site, H1+ is bonded in a single-bond geometry to one C+0.57- atom. In the second H1+ site, H1+ is bonded in a single-bond geometry to one C+0.57- atom. In the third H1+ site, H1+ is bonded in a single-bond geometry to one C+0.57- atom. In the fourth H1+ site, H1+ is bonded in a single-bond geometry to one C+0.57- atom. In the fifth H1+ site, H1+ is bonded in a single-bond geometry to one C+0.57- atom. In the sixth H1+ site, H1+ is bonded in a single-bond geometry to one C+0.57- atom. In the seventh H1+ site, H1+ is bonded in a single-bond geometry to one C+0.57- atom. In the eighth H1+ site, H1+ is bonded in a single-bond geometry to one C+0.57- atom. In the ninth H1+ site, H1+ is bonded in a single-bond geometry to one C+0.57- atom. In the tenth H1+ site, H1+ is bonded in a single-bond geometry to one C+0.57- atom. In the eleventh H1+ site, H1+ is bonded in a single-bond geometry to one C+0.57- atom. In the twelfth H1+ site, H1+ is bonded in a single-bond geometry to one C+0.57- atom. In the thirteenth H1+ site, H1+ is bonded in a single-bond geometry to one C+0.57- atom. In the fourteenth H1+ site, H1+ is bonded in a single-bond geometry to one C+0.57- atom. In the fifteenth H1+ site, H1+ is bonded in a single-bond geometry to one C+0.57- atom. In the sixteenth H1+ site, H1+ is bonded in a single-bond geometry to one C+0.57- atom. In the seventeenth H1+ site, H1+ is bonded in a single-bond geometry to one C+0.57- atom. In the eighteenth H1+ site, H1+ is bonded in a single-bond geometry to one C+0.57- atom. In the nineteenth H1+ site, H1+ is bonded in a single-bond geometry to one C+0.57- atom. In the twentieth H1+ site, H1+ is bonded in a single-bond geometry to one C+0.57- atom. In the twenty-first H1+ site, H1+ is bonded in a single-bond geometry to one C+0.57- atom. In the twenty-second H1+ site, H1+ is bonded in a single-bond geometry to one C+0.57- atom. In the twenty-third H1+ site, H1+ is bonded in a single-bond geometry to one C+0.57- atom. In the twenty-fourth H1+ site, H1+ is bonded in a single-bond geometry to one C+0.57- atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on H8C5 by Materials Project

(CH)2(CH2)3 crystallizes in the tetragonal P-42_1c space group. The structure is zero-dimensional and consists of eight methane molecules and twelve methane molecules.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on HC by Materials Project

CH is Cubane-like structured and crystallizes in the trigonal P-3m1 space group. The structure is zero-dimensional and consists of two methane molecules. C is bonded in a distorted single-bond geometry to one H atom. The C–H bond length is 1.11 Å. H is bonded in a single-bond geometry to one C atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on HC by Materials Project

CH is Cubane-like structured and crystallizes in the cubic I2_13 space group. The structure is zero-dimensional and consists of eight methane molecules. C is bonded in a single-bond geometry to one H atom. The C–H bond length is 1.09 Å. H is bonded in a single-bond geometry to one C atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on H34C19 by Materials Project

(CH3)3(CH2)7(CH)4C5H7 crystallizes in the monoclinic P2_1 space group. The structure is zero-dimensional and consists of eight methane molecules, fourteen methane molecules, six methane molecules, and two neopentane molecules.

36 MATERIALS SCIENCE↗
DOE OSTI2025

Superclustering with the Atacama Cosmology Telescope and Dark Energy Survey. II. Anisotropic Large-scale Coherence in Hot Gas, Galaxies, and Dark Matter

Statistics that capture the directional dependence of the baryon distribution in the cosmic web enable unique tests of cosmology and astrophysical feedback. We use constrained oriented stacking of thermal Sunyaev–Zel’dovich (tSZ) maps to measure the anisotropic distribution of hot gas 2.5–40 Mpc away from galaxy clusters embedded in massive filaments and superclusters. The cluster selection and orientation (at a scale of ∼15 Mpc) use Dark Energy Survey (DES) Year 3 data, while expanded tSZ maps from the Atacama Cosmology Telescope Data Release 6 enable a ∼3× more significant measurement of the extended gas compared to the technique’s proof-of-concept. Decomposing stacks into cosine multipoles of order m , we detect a dipole ( m = 1) and quadrupole ( m = 2) at 8σ–10σ, as well as evidence for m = 4 signal at up to 6σ, indicating sensitivity to late-time non-Gaussianity. We compare to Cardinal simulations with spherical gas models pasted onto dark matter halos. The fiducial tSZ data can discriminate between two models that deplete pressure differently in low-mass halos (mimicking astrophysical feedback), preferring higher average pressure in extended structures. However, uncertainty in the amount of cosmic infrared background contamination reduces the constraining power. Additionally, we apply the technique to DES galaxy density and weak lensing to study for the first time their oriented relationships with tSZ. In the tSZ-to-lensing relation, averaged on 7.5 Mpc (transverse) scales, we observe dependence on redshift but not shape or radial distance. Thus, on large scales, the superclustering of gas pressure, galaxies, and total matter is coherent in shape and extent.

79 ASTRONOMY AND ASTROPHYSICS↗
NASA NTRS1998

Differential Thermal Analysis of Hg(1-x)Mn(x)Te Alloys in the X=0 to 0.3 Range

Understanding the experimental conditions necessary for the development of radial and axial compositional homogeneity in directionally solidified Hg(0.89)Mn(0.11)Te(MMT) crystals has been difficult due to the lack of segregation coefficient data on the Hg(1-x)Mn(x)Te alloy system in the X = 0 to 0.3 composition range. Determining segregation coefficient data from the available Hg(1-x)Mn(x)Te alloy phase equilibria data is not practical due to discrepancies in the shape of the reported solidus and liquidus curves in the X = 0 to 0.3 range. To resolve these discrepancies and to obtain segregation coefficient data which can be used to understand homogeneity in directionally solidified MMT crystals, the solidus and liquidus temperatures of seven Hg(1-x)Mn(x)Te alloys in the X = 0 to 0.3 range were determined using differential thermal analysis (DTA). The Hg(1-x)Mn(x)Te phase diagram constructed for the X = 0 to 0.3 range of this alloy system from the DTA measurements clarifies the shape of the solidus and liquidus curves in this range. The segregation coefficient for the Hg(1-x)Mn(x)Te system was found to vary from 5 to 4.4 as the solidus composition increased from 0-30 atomic percent MnTe. This information will be useful in the analysis of axial and radial homogeneity of directionally solidified MMT crystals.

Price, M. W.↗
NASA NTRS2000

The Evolution of Tropospheric Temperature Field and its Relationship With The Onset of Asian Summer Monsoon

The mean state and year-to-year variations of the tropospheric temperature fields and their relationship with the establishment of the summertime East Asian monsoon (EAM) and the Indian monsoon (INM) are studied using the NCEP reanalysis data of 15 years (1982-1996). The results show that the seasonal shift of the South Asian High in the upper troposphere and the establishment of the EAM and the INM are closely related to the seasonal warming which causes a reversal of the meridional gradient of upper tropospheric mean temperature over the monsoon regions. On the average of 15 years, the reversal time of the temperature gradient in the EAM region (INM region) is concurrent with (one pentad earlier than) the onset time of the summer monsoon. In most years of the 15-year period, the reversal of temperature gradient coincides or precedes the onset time of the summer monsoon in both the EAM region and the INM region. The results suggest an important role of thermal processes on the establishment of the Asian monsoon. The contributors to the upper tropospheric warming over the EAM region are the strong horizontal warm advection and the diabetic heating against the adiabatic cooling due to upward motion. In the INM region, strong adiabatic heating by subsidence and the diabetic heating are major warming processes against the strong horizontal cold advection related to the persistent northwestlies to the southwestern periphery of the Tibetan Plateau. It appears that the early or late establishment of the Asian summer monsoon is not directly related to the differential warming near the surface.

He, H.↗
NASA NTRS2000

Homoepitaxial ZnO Film Growth

ZnO films have high potential for many applications, such as surface acoustic wave filters, UV detectors, and light emitting devices due to its structural, electrical, and optical properties. High quality epitaxial films are required for these applications. The Al2O3 substrate is commonly used for ZnO heteroepitaxial growth. Recently, high quality ZnO single crystals are available for grow homoepitaxial films. Epitaxial ZnO films were grown on the two polar surfaces (O-face and Zn-face) of (0001) ZnO single crystal substrates using off-axis magnetron sputtering deposition. As a comparison, films were also deposited on (0001) Al2O3 substrates. It was found that the two polar ZnO surfaces have different photoluminescence (PL) spectrum, surface structure and morphology, which strongly influence the epitaxial film growth. The morphology and structure of homoepitaxial films grown on the ZnO substrates were different from heteroepitaxial films grown on the Al2O3. An interesting result shows that high temperature annealing of ZnO single crystals will improve the surface structure on the O-face surface rather than the opposite surface. The measurements of PL, low-angle incident x-ray diffraction, and atomic force microscopy of ZnO films indicate that the O-terminated surface is better for ZnO epitaxial film growth.

Zhu, Shen↗
NASA NTRS1994

Galileo Spacecraft Scan Platform Celestial Pointing Cone Control Gain Redesign

During September and October 1991, pictures of the Gaspra asteroid and neighboring stars were taken by the Galileo Optical Navigation (OPNAV) Team for the purpose of navigation the spacecraft for a successful Gaspra encounter. The star tracks in these pictures showed that the scan platform celestial pointing cone controller performed poorly in compensating for wobble-induced cone offsets.

Gaspar asteroid Galileo Optical Navigation (OPNAV)↗
NASA NTRS2012

The Advanced Technology Microwave Sounder (ATMS): The First 10 Months On-Orbit

The Advanced Technology Microwave Sounder (ATMS) is a new satellite microwave sounding sensor designed to provide operational weather agencies with atmospheric temperature and moisture profile information for global weather forecasting and climate applications. A TMS will continue the microwave sounding capabilities first provided by its predecessors, the Microwave Sounding Unit (MSU) and Advanced Microwave Sounding Unit (AMSU). The first ATMS was launched October 28, 2011 on board the NPOESS Preparatory Project (NPP) satellite. Microwave soundings by themselves are the highest-impact input data used by Numerical Weather Prediction (NWP) models, especially under cloudy sky conditions. ATMS has 22 channels spanning 23-183 GHz, closely following the channel set of the MSU, AMSU-A1/2, AMSU-B, Microwave Humidity Sounder (MHS), and Humidity Sounder for Brazil (HSB). All this is accomplished with approximately 1/4 the volume, 1/2 the mass, and 1/2 the power of the three AMSUs. A description of ATMS cal/val activities will be presented followed by examples of its performance after its first 10 months on orbit.

Kim, Edward↗
NASA NTRSDate not supplied

High resolution assimilation of multiple satellite retrievals with emissions adjustment to improve air quality forecasting with WRF-Chem/DART

We will present results from medium (15km, 6hr cycling) and high (4 km, 6 hr cycling) spatiotemporal resolution applications of the WRF-Chem/DART ensemble, regional, air quality (AQ) forecast/assimilation system.The medium-resolution setup is applied to the Discover AQ/Front Range Air Pollution and Photochemistry Experiment (FRAPPE) domain from July 14 to July 29, 2014. The high-resolution setup is applied to a Colorado domain from July 14 to July 29, 2020. For the FRAPPE application, we assimilate MOPITT CO; IASI CO;MODIS AOD; OMI O3, NO2; and AirNow CO, O3, NO2, SO2, PM10, and PM2.5. For the Colorado application, we assimilate the same MOPITT, MODIS, and AirNow constituents as in the FRAPPE application and TROPOMI CO, O3, NO2; and synthetic TEMPO O3and NO2. WRF-Chem/DART integrates the Weather Research and Forecast (WRF) model with on-line chemistry (WRF-Chem) into the Data Assimilation Research Testbed (DART). It assimilates AirNow CO, O3, NO2, SO2, PM10, and PM2.5 measurements, MOPITT CO; IASI CO, O3; OMI O3, NO2, SO2; TROPOMI CO, O3, NO2, SO2; MODIS AOD; and synthetic TEMPO O3 and NO2 total/partial column and/or profile retrievals.WRF-Chem/DART uses: (i) the state augmentation method for adjusting emissions; (ii) state-space localization; and (iii) a near-real time scripting system. We use the medium-resolution FRAPPE application to demonstrate the incremental benefits from assimilating OMI observations with emissions adjustment and the high-resolution Colorado application to demonstrate the incremental benefits from assimilating syntheticTEMPO observations with emissions adjustment. For both applications, we expect that: (i) assimilating chemical observations will increaseAQ forecast skill; (ii) including emissions adjustment will increase forecast skill/predictability; and (iii) including assimilation of synthetic TEMPO observations will further increase forecast skill/predictability.

High resolution↗
NASA NTRS2021

The 450 Day X-Ray Monitoring of the Changing-look AGN 1ES 1927+654

1ES 1927+654 is a nearby active galactic nucleus (AGN) that underwent a changing-look event in early 2018, developing prominent broad Balmer lines that were absent in previous observations. We have followed up this object in the X-rays with an ongoing campaign that started in 2018 May and that includes 265 NICER (for a total of 678 ks) and 14 Swift/XRT (26 ks) observations, as well as three simultaneous XMM-Newton/NuSTAR (158/169 ks) exposures. In the X-rays, 1ES 1927+654 shows a behavior unlike any previously known AGN. The source is extremely variable both in spectral shape and flux and does not show any correlation between X-ray and UV flux on timescales of hours or weeks/months. After the outburst, the power-law component almost completely disappeared, and the source showed an extremely soft continuum dominated by a blackbody component. The temperature of the blackbody increases with the luminosity, going from kT∼80 eV (for a 0.3–2 keV luminosity ofL0.3−2∼1041.5erg s−1) to∼200 eV (forL0.3−2∼1044erg s−1). The spectra show evidence of ionized outflows and of a prominent feature at ∼1 keV, which can be reproduced by a broad emission line. The unique characteristics of1ES 1927+654 in the X-ray band suggest that it belongs to a new type of changing-look AGN. Future X-ray surveys might detect several more objects with similar properties.

Astrophysical black holes↗