Context. In November 2019, eROSITA on board of the Spektrum-Roentgen-Gamma (SRG) observatory started to map the entire sky in X-rays. After the four-year survey program, it will reach a flux limit that is about 25 times deeper than ROSAT. During the SRG performance verification phase, eROSITA observed a contiguous 140 deg2 area of the sky down to the final depth of the eROSITA all-sky survey (eROSITA Final Equatorial-Depth Survey; eFEDS), with the goal of obtaining a census of the X-ray emitting populations (stars, compact objects, galaxies, clusters of galaxies, and active galactic nuclei) that will be discovered over the entire sky. Aims. This paper presents the identification of the counterparts to the point sources detected in eFEDS in the main and hard samples and their multi-wavelength properties, including redshift. Methods. To identifyy the counterparts, we combined the results from two independent methods (NWAY and ASTROMATCH), trained on the multi-wavelength properties of a sample of 23k XMM-Newton sources detected in the DESI Legacy Imaging Survey DR8. Then spectroscopic redshifts and photometry from ancillary surveys were collated to compute photometric redshifts. Results. Of the eFEDS sources, 24 774 of 27 369 have reliable counterparts (90.5%) in the main sample and 231 of 246 sourcess (93.9%) have counterparts in the hard sample, including 2514 (3) sources for which a second counterpart is equally likely. By means of reliable spectra, Gaia parallaxes, and/or multi-wavelength properties, we have classified the reliable counterparts in both samples into Galactic (2695) and extragalactic sources (22 079). For about 340 of the extragalactic sources, we cannot rule out the possibility that they are unresolved clusters or belong to clusters. Inspection of the distributions of the X-ray sources in various optical/IR colour-magnitude spaces reveal a rich variety of diverse classes of objects. The photometric redshifts are most reliable within the KiDS/VIKING area, where deep near-infrared data are also available. Conclusions. This paper accompanies the eROSITA early data release of all the observations performed during the performance and verification phase. Together with the catalogues of primary and secondary counterparts to the main and hard samples of the eFEDS survey, this paper releases their multi-wavelength properties and redshifts.
We present the results of a γ-ray likelihood analysis over all the extreme and high synchrotron peak blazars (EHSP & HSP) from the 3HSP sample. We investigate 2013 multifrequency seed positions under the eyes of Fermi Large Area Telescope, considering 11 years of observations. We report on 1160 γ-ray signatures detected down to the 3 σ threshold in the energy range between 500 MeV to 500 GeV. The detections include 235 additional sources concerning 4FGL, all confirmed via high-energy TS maps, and represent an improvement of ∼25% for the number of EHSP & HSP currently described in γ-rays. We build the γray spectral energy distribution for all the 1160 sources, delivering to the very high-energy community a dedicated spectral description of the entire 3HSP population. We plot the γray logN-logS for the 3HSP sample, and also for the EHSP & HSP subsamples. We measure the total contribution of HSP+EHSP to the extragalactic gamma-ray background, which reaches up to ∼33% at 100 GeV. Also, we show how does the γ-ray detectability improves according to the synchrotron peak flux as represented by the Figure of Merit (FOM) parameter. We highlight that the search for TeV peaked blazars may benefit from considering HSP and EHSP as a whole, instead of EHSPs only. We entitle this γ-ray sample as Second Brazil-ICRANet Gamma-ray Blazar catalog, with the acronym 2BIGB. All information will be available on public data repositories (Brazilian Science Data Center-BSDC, OpenUniverse, GitHub https://github.com/BrunoArsioli), including the broadband models and the spectral energy distribution data points.2 TeVcat:http://tevcat.uchicago.edu/ is a regularly updated list of TeV detected astrophysical sources. From there we count 81 extragalactic TeV sources, which includes 72 blazars, 3 Starbursts, 1 Globular Cluster, 2 AGNs of unknown type and 3 gamma-ray bursts.
We analyze Near-Infrared Integral Field Spectrograph (NIFS) observations of the type-2 quasar (QSO2) SDSS J094521.33+173753.2 to investigate its warm molecular and ionized gas kinematics. This QSO2 has a bolometric luminosity of 10 45.7 erg s −1 and a redshift of z = 0.128. The K-band spectra provided by NIFS cover a range of 1.99-2.40 µm where low-ionization (Paα and Brδ), high ionization ([S XI]λ1.920 µm and [Si VI]λ1.963 µm) and warm molecular lines (from H 2 1-0S(5) to 1-0S(1)) are detected, allowing us to study the multi-phase gas kinematics. Our analysis reveals gas in ordinary rotation in all the emission lines detected and also outflowing gas in the case of the low-and high-ionization emission lines. In the case of the nuclear spectrum, which corresponds to a circular aperture of 0.3 (686 pc) in diameter, the warm molecular lines can be characterized using a single Gaussian component of full width at half maximum (FWHM)= 350-400 km s −1 , while Paα, Brδ, and [Si VI] are best fitted with two blue-shifted Gaussian components of FWHM∼800 and 1700 km s −1 , in addition to a narrow component of ∼300 km s −1 . We interpret the blue-shifted broad components as outflowing gas, which reaches the highest velocities, of up to −840 km s −1 , in the south-east direction (PA∼125 • ), extending up to a distance of ∼3.4 kpc from the nucleus. The ionized outflow has a maximum mass outflow rate of Ṁout, max =42-51 M yr −1 , and its kinetic power represents 0.1% of the quasar bolometric luminosity. VLA data of J0945 show extended radio emission (PA∼100 • ) that is aligned with the clumpy emission traced by the narrow component of the ionized lines up to scales of several kpc, and with the innermost part of the outflow (central ∼0.4 = 915 pc). Beyond that radius, at the edge of the radio jet, the high-velocity gas shows a different PA, of ∼125 • . This might be indicating that the line-emitting gas is being compressed and accelerated by the shocks generated by the radio jet.
Theoretical models of the co-evolution of galaxies and active galactic nuclei (AGNs) ascribe an important role in the feedback process to a short, luminous, obscured, and dust-enshrouded phase during which the accretion rate of the supermassive black hole is expected to be at its maximum and the associated AGN-driven winds are also predicted to be maximally developed. To test this scenario, we have isolated a textbook candidate from the eROSITA Final Equatorial-Depth Survey (eFEDS) obtained within the performance and verification program of the eROSITA telescope on board the Spectrum Röntgen Gamma mission. From an initial catalogue of 246 hard X-ray selected sources that are matched with the photometric and spectroscopic information available within the eROSITA and Hyper Suprime-Cam consortia, three candidates quasars in the feedback phase have been isolated applying a diagnostic proposed previously. Only one source (eFEDS J091157.4+014327) has a spectrum already available (from SDSS-DR16, z = 0.603) and it unambiguously shows abroad component (full width at half maximum ~1650 kms−1) in the [OIII]5007 line. The associated observed L[OIII] is ~2.6 × 1042 erg s−1, one to two orders of magnitude higher than that observed in local Seyfert galaxies and comparable to those observed in a sample of z ~ 0.5 type 1 quasars. From the multi-wavelength data available, we derive an Eddington ratio (Lbol/LEdd) of ~0.25 and a bolometric correction in the hard X-ray band of kbol ~ 10, which is lower than the corrections observed for objects at similar bolometric luminosity. These properties, along with the outflow, the high X-ray luminosity, the moderate X-ray obscuration (LX∽1044.8 erg s−1, NH∽2.7 × 1022 cm−2), and the red optical colour, all match the prediction of quasars in the feedback phase from merger-driven models. Forecasting to the full eROSITA all-sky survey with its spectroscopic follow-up, we predict that by the end of 2024, we will have a sample of few hundred such objects at z= 0.5–2.
We present a systematic study of gamma-ray blazar candidates based on a sample of 40 objects taken from the WIBR catalogue. By using a likelihood analysis, 26 of the 40 sources showed significant gamma-ray signatures ⩾ 3σ. Using high-energy test statistics (TS) maps, we confirm 8 sources, which are completely new, and show another 15 promising γ-ray candidates. The results from this analysis show that a multi-frequency approach can help to improve the current description of the gamma-ray sky.
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