Understanding the physical characteristics of small bodies in the Solar System is crucial for refining models of their formation and evolution. Although several kilometre-sized asteroids have already been visited by spacecraft, 1998 KY26 will be the first asteroid in the decametre range to be explored in situ. Its diameter and spin period place it above the spin barrier, suggesting that its formation and properties may differ from those of previously visited bodies. However, the key physical characteristics of 1998 KY26 remain poorly understood. We conducted a photometric observing campaign during 1998 KY26’s close approach to Earth in 2024. Our observations revealed that 1998 KY26 has a high optical albedo and colours consistent with an E-type taxonomy. We also determined its spin period to be (5.3516 ± 0.0001) minutes—twice as fast as previously reported. Using lightcurve inversion methods, we derived a retrograde pole solution and constructed convex and non-convex shape models. By integrating these models with Goldstone radar data from 1998, we estimated 1998 KY26’s diameter to be (11 ± 2) m. The most likely structure for 1998 KY26 is monolithic, yet a fine grained rubble-pile structure is theoretically possible given its required small strength level. We found that it will be possible to validate these results with future JWST observations. Our comprehensive characterisation of 1998 KY26 can inform the planning of the Hayabusa2# spacecraft’s rendezvous encounter, scheduled for July 2031. Additionally, it provides valuable insights into the non-gravitational forces acting on small Solar System bodies, enhancing our understanding of their orbital evolution which could shed light on the nature of dark comets.
Asteroids are the remnant blocks of the early stages of the formation of our Solar System. In particular, those classified as “primitive” are believed to contain the most pristine and almost unprocessed materials (water-bearing minerals, carbon compounds, and organics), and therefore they provide unique information on the formation and evolution of our planetary system, including how water appeared on Earth. Among these objects, primitive near-Earth asteroids (NEAs) are of particular interest. Due to their proximity they are impact hazards to Earth, but they are also the ideal targets for space missions. That is the case of primitive NEAs (101955) Bennu and (162173) Ryugu, primary targets of NASA’s OSIRIS-REx and JAXA’s Hayabusa 2 sample return missions, respectively, currently on their way to encounter the two asteroids. The main asteroid belt, located between the orbits of Mars and Jupiter (2.1-5.2 AU), and in particular collisional families, are currently considered the principal source of NEAs (Bottke et al. 2002; Bottke et al. 2005). In the case of the two primitive NEAs mentioned above, several studies have shown that the most likely source is the Polana collisional family (Campins et al. 2010, 2013), a primitive family located in the inner belt. Other large primitive families in that region are Erigone, Sulamitis, and Clarissa. Smaller primitives families like Klio, Chaldaea, Svea and Chimaera can also be found in the same region (Nesvorny et al. 2015).With the main objective of supporting the science return of OSIRIS-Rex and Hayabusa 2, in 2010 our group started a coordinated effort to characterize the surface composition of primitive asteroids not only in the collisional families of the inner belt, but in the central and outer belt: our PRIMitive Asteroids Spectroscopic Survey (PRIMASS) includes both visible and near-infrared spectra. Up to now, in the frame of PRIMASS, our group has studied several primitive families wihtin the inner main belt: the Polana-Eulalia complex (de León et al. 2016; Pinilla-Alonso et al. 2016), Erigone (Morate et al. 2016), Sulamitis and Clarissa (Morate et al. 2018a), and Klio, Chaldaea, Chimaera, and Svea (Morate et al. 2019). One interesting result was that Erigone. Sulamitis, Klio, Chaldaea, and Chimaera, presented different percentages of asteroids with an absorption band centered at 0.7μm and associated to hydrated silicates, while the Polana, Clarissa, and Svea families showed no signs of hydration. This result remarks the need for spectral characterization as even the families classified all a priori as primitive can show compositional differences.Continuing with our PRIMASS survey, we started the characterization of the families in the central part of the belt (2.50-2.82 AU). According to Nesvorný et al. (2015), there are at least 5 primitive families in that region, and for the present work we have focused on three of them: Padua, Nemesis, and Hoffmeister. As it can be seen in Fig. 1A, they overlap in the (a, i) orbital parameter space, and two of them overlap even in the (a, e) space. This might be indicative of a common origin and interestingly, the three families show a similar age. They also overlap in the (a, H) space (Fig. 1B), which make them an ideal case to see if we can discriminate between members from each family using spectroscopy. According to the taxonomical classification of their largest member using visible spectra, Hoffmeister is classified as a CF type family (neutral to blue spectral slope), Nemesis is a C-type family (neutral slope), and Padua is an X-type (redder slope). The distribution of WISE albedos (Mainzer et al. 2011) of Hoffmeister is rather different from what is seen on Nemesis and Padua (Fig. 1C), also indicative of different composition. Only spectra will help to compositionally characterize these families and to search for the presence of the 0.7 μm absorption band associated to hydration. This will allow us to compare the level of hydration in families from the inner to the outer belt (De Prá et al. 2017) and map the water inventory of the asteroid belt to constrain evolutionary models.Figure 1: A) Distribution of the members of the three primitive collisional families in semimajor axis (a) vs. Eccentricity (top panel) and sine of inclination (bottom panel). The three families clearly overlap in the (a,i) space. B) Distribution of the three families in the absolute magnitude (H) - a space. There are clear overlapping regions where we can test if members of each family can be identified using spectra. C) Distribution of the albedos measured by WISE for the members of the three families.In order to study these three families, we obtained visible spectra for a total of 124 asteroids (44 within the Nemesis and Hoffmeister families, and 36 within the Padua family) using the OSIRIS spectrograph at the 10.4m GTC, located at the Observatorio Del Roque de Los Muchachos (La Palma, Spain). In this work, we will present the first spectroscopic study of the Nemesis, Hoffmeister, and Padua families, and we will compare the results with those obtained for the families located in the inner main belt.
Introduction: Comet P/2019 LD2 (ATLAS) was discovered early June 2019 as a faint asteroidal object and initially classified as a Jupiter Trojan. In depth inspection of images obtained during 2019 revealed that the object is active. No signs of cometary-like activity have been detected on any Jupiter Trojans until now, despite it is widely accepted that they are captured objects from the outer solar system. For that reason, we scheduled P/2019 LD2 observations with the world’s largest optical telescope, the 10.4m Gran Telecopio CANARIAS (GTC) to study its nature as soon as it became visible in May 2020In the meantime, Kareta et al. (2020) showed that the comet had experienced a close encounter with Jupiter on February 17, 2017 at 0.092 AU, well inside the Hill radius of the planet, 0.338 AU. They conclude that it is a recently captured Centaur, not a Jupiter Trojan.Even if P/2019 LD2 is not the first active Jupiter Trojan, it is a very interesting object that could help to better understand the transition from Centaur to JFC. Its orbit just beyond Jupiter and its activity are evocative of 29P/Schwassmann-Wachmann, an object considered as a prototypical "gateway" between the Centaurs and JFCs by Sarid et al. (2019). Observations: We present the observations of P/2019 LD2 (ATLAS) obtained on 2020 May 16 and 17 using the OSIRIS camera-spectrograph of the 10.4 m GTC.On May 16 we obtained images , using the Sloan g’,r’,i’,z’ filters that were used to characterize its overall level of cometary activity using a Monte Carlo dust tail fitting code as described in various papers (see, e.g. Moreno et al. 2016, 2017, and references therein). The comet presents a conspicuous coma and tail as seen Fig. 1.We also obtained two visible spectra of P/2019 LD2 on May 17 with the aim of looking for signatures of the typical gas species observed in comets. Each individual spectra consisted of an exposure of 600 seconds using the R300B grism and the 1.49′′ slit width, covering a wavelength range from 3600 to 7500 Å, and with a dispersion of 4.96 Å/pix for a 0.6′′ slit. Fig. 1 Left panel: A comparison of the observed (black contours) and modeled (red contours) tail brightness isophotes. The innermost contour corresponds to 8×10−14 solar disk units, and the brightness decrease in factors of two outwards. The images are rotated to the conventional North- up, East-to-the-left orientation. The x- and y-axis are labeled in km projected on the sky at the object distance. Right panel: A comparison of observed (black line) and modeled (red line) tail brightness along the direction described by the blue dotted line in the left panel. Past, present and future dynamical evolution: The assessment of the dynamical evolution of P/2019 LD2 requires the analysis of an extensive sample of N-body simulations. In this work, we have used the approach discussed in de la Fuente Marcos & de la Fuente Marcos (2019) and Licandro et al. (2019) to study the past, present and future evolution. Results: Our results can be summarized as follows:(i) P/2019 LD2 shows a conspicuous coma and tail with a longitude > 1′.(ii) There is no evidence of CN, C2 or C3 emission within the 3-σ level in the comet spectrum. In particular there are no signs of the CN (0-0) emission at 3880 Å that it is usually the strongest emission observed in comets.(iii) According to our model, the dust emission of P/2019 LD2 can be described by a Gaussian with a FWHM=180 days, a maximum (dM/dt)0 = 50 kg s−1 attained on 2019 November 27 (t =170 days from the observations) that then decreases again, with a current (2020 May 16) dust loss rate of 5 kg s−1. This implies a total dust mass loss of 9×108 kg since the start of the dust emission, and almost no dust emission when observed in 2018.(v) The origin of activity is most likely linked to a thermally driven process, likely associated to sublimation of crystalline water ice and clathrates(vi) The nucleus corresponds to a km-size object (with radius between 1.5 and 3.5 km), in the size-range of the JFCs.(vii) P/2019 LD2 is now an ephemeral co-orbital of Jupiter, following what looks like a short arc of a quasi-satellite cycle that started in 2017 and will end in 2028. It will experience a very close encounter with Jupiter at ∼10 Jovian radii on January 18, 2063. If it survive the close approach, its probability of escaping the solar system during the next 0.5 Myr is 0.48±0.02(ix) The origin of P/2019 LD2 is still an open question. The probability of this comet having been captured from interstellar space during the last 0.5 Myr is 0.50±0.03, 0.79±0.06 during the last 2 Myr and to 0.89±0.07 for 4 Myr, suggesting that P/2019 LD2 can be a captured interstellar comet. Anyhow, a very close encounter with one of the giant planets of a former member of the scattered disk may have produced a fragmentation event induced by the planetary tidal force that was eventually able to form the observed, present-day, P/2019 LD2 . Referencesde la Fuente Marcos, C., de la Fuente Marcos, R., Licandro, J., Serra-Ricart, M.,& Cabrera-Lavers, A. 2019, Research Notes of the American AstronomicalSociety, 3, 143Kareta, T., Volk, K., Noonan, J. W., et al. 2020, Research Notes of the AmericanAstronomical Society, 4, 74Licandro, J., de la Fuente Marcos, C., de la Fuente Marcos, R., et al. 2019, A&A,Moreno, F., Pozuelos, F. J., Novakovic ́, B., et al. 2017, ApJ, 837, L3Moreno, F., Snodgrass, C., Hainaut, O., et al. 2016, A&A, 587, A155Sarid, G., Volk, K., Steckloff, J. K., et al. 2019, ApJ, 883, L25
The 10.4m Gran Telescopio Canarias (GTC) was designed to be a versatile telescope, able to serve a wide scientific community. To this aim, various focal stations have been equipped, including a Cassegrain, two Nasmyth foci, and four folded-Cassegrain stations. This allows an ambitious instrumentation plan to be developed. We present the latest developments and plans, with emphasis on the most relevant and innovative features. They include: new detectors and cryogenic (pulse tube) systems for the main GTC instruments, the migration of the HiPERCAM imager to a dedicated focus with an ad-hoc rotator; the commissioning of the single-conjugated AO system for the GTC; the preparation to host in the Coud ' e room a fiber-fed UV and optical spectrograph which aims at a 10 cm s(-1) radial velocity precision; and the plan for the future instruments, which include the upgrading of the adaptive optics system and the development of an imager and spectrograph covering simultaneously the optical and near-infrared domains.
This study delves into the intricate kinematic behavior of ionized gas within IZw18, a galaxy known for its remarkably low metallicity and proximity. Leveraging data from MEGARA/GTC, we meticulously analyzed the galaxy's structure and dynamics using Hα line profiles. Employing single and double Gaussian component fittings, we generated detailed maps of luminosity, velocity, and velocity dispersion across both the main body (MB) and Halo regions. By extracting integrated spectra from various galactic zones, we enhanced the signal-to-noise (S/N) ratio. In the MB, a clear rotational pattern emerged, supplemented by a more intricate kinematic structure from the double-component fitting, notably featuring a broad component with a FWHM nearing 2000 km/s. This broad component, exhibiting wide spatial extension, hints at a high-energy outflow and suggests non-localized sources of significant kinetic energy. The considerable velocity disparities between narrow and broad components imply potential spatial segregation, possibly due to dense gas near the kinematic origin acting as a momentum-reflection 'wall'. Examining the halos, the NE Halo appears tranquil with low velocity dispersions, while the SW Halo displays higher velocities and complex kinematics, indicative of varied dynamic interactions. The presence of the broad component throughout the MB and the intricate kinematics across all regions suggests widespread and subtle turbulent motion. This nuanced understanding of IZw18's kinematic behavior, elucidating the interplay of gas components and internal structures, enriches our comprehension of dynamics in blue compact dwarf galaxies. It holds promise for shedding light on early galaxy formation and the complex kinematics inherent to such environments.
ABSTRACT We present the results of observations of asteroid (248370) QN173 obtained during July 2021–January 2022 with three telescopes. Our analysis revealed the presence of the dust tail for about half of a year. The direct images of the asteroid were obtained with broad-band filters. No emissions were revealed in the spectra, and the spectrum of the asteroid closely matched that of a C-type asteroid. Created colour and linear polarization variations along the tail were analysed. The asteroid demonstrated a redder colour compared to the Sun. Dramatic changes in dust productivity obtained in different filters were not detected. The g − r colour changes from 0.2m to 0.7m over the coma, and the linear polarization degree varies from about 1.2 per cent to 0.2 per cent and from −0.2 per cent to −1.5 per cent at the phase angle of 23.2° and 8.16°. The total dust mass ejected until the latest observation on October 10 is 4.2 × 107 kg, with a maximum rate of 2.6 kg s−1 based on the Monte Carlo modelling of the dust tail. The estimated asteroid size is 1.3 km. It is shown that large particles are concentrated around the nucleus, whereas smaller ones dominate in the tail. The evolution of (248370) QN173 orbit and the orbits of the sample of the 464 short-periodic comets were followed. Ten of them approached the asteroid’s orbit. These objects are not genetically related, despite very close distance of their orbits for a relatively long time.
We have conducted long-slit spectroscopic observations and analyzed archival radio data for the ultraluminous X-ray source (ULX) NGC 4861 X-1. Our spectral line analysis unveils NGC 4861 X-1 as the fourth ULX situated within an X-ray photoionized nebula, following three previous findings made approximately two decades ago. Remarkably, we discover NGC 4861 X-1 also possesses a radio nebula emitting optically thin synchrotron radiation, which contradicts its X-ray photoionization and raises doubts about the four ULXs being a mere coincidence. Instead of gradually accumulating from different bands bit by bit, our multiband discovery is made all at once. Moreover, we tentatively perceive a faint continuum spectrum of the optical nebula. Further observations are needed to ascertain its radio structures and verify the optical continuum.
This work presents the analysis of seven mutual events of the Patroclus–Menoetius system (PMS) observed during the last season of mutual events, in 2017–2018. We compare the obtained light curves with those predicted using Grundy et al. and discuss the differences in the timing of the events and the drop of magnitude. Based on models of these observations, we present a collection of orbital parameters that provide the best fit for the observed events and compare the new solutions for the orbit of the system with solutions provided in the literature. Furthermore, we also discuss an interesting finding in the light curve of the only superior event in our collection. This light curve (the one with the best signal-to-noise ratio in our data set) shows the imprint of a possible crater in the south pole of Menoetius as deep as a fourth of its radius.
Model-based systems engineering has as one of its central pillars the single source of truth that is usually a CAD model, or a model defined using a language such as SysML. However, having a single point of truth is not incompatible with using multiple modeling languages. A simple DSL like PORIS allows us to make instrument sketches much more concise and understandable than if we made them in SysML. By providing this language with transformers, we can automatically and instantly generate configuration panels, diagrams and documentation that allow the scientific team of the instrument to create more quickly and formally the configuration and functional specifications of the instrument. Engineers can also create a high percentage of the instrument software, for instance, the ones related to configuration, monitoring, diagnostics or safety. In this article we will show how, starting from a simple model in a spreadsheet, we will end integrating its software in the GTC control system.
Since the discovery of chemically peculiar stars in globular clusters in the last century, the study of multiple populations has become increasingly important, given that chemical inhomogeneity is found in almost all globular clusters. Despite various proposed theories attempting to explain this phenomenon, fitting all the observational evidence in globular clusters with one single theory remains notoriously difficult and currently unsuccessful. In order to improve existing models and motivate new ones, we are observing globular clusters at critical conditions, e.g., metal-rich end, metal-poor end, and low mass end. In this paper, we present our first attempt to investigate multiple populations in low mass globular clusters. We obtained low-resolution spectra around 4000 A of 30 members of the globular cluster Palomar 13 using OSIRIS/Multi-object spectrograph mounted at the Gran Telescopio Canarias. The membership of red giant branch stars is confirmed by the latest proper motions from Gaia DR2 and literature velocities. After comparing the measured CN and CH spectral indices with those of the stellar models, we found a clear sign of nitrogen variation among the red giant branch stars. Palomar 13 may be the lowest mass globular cluster showing multiple populations.
Context. The evolution of galaxies through cosmic time is studied observationally by means of extragalactic surveys. The usefulness of these surveys is greatly improved by increasing the cosmological volume, in either depth or area, and by observing the same targets in different wavelength ranges. A multi-wavelength approach using different observational techniques can compensate for observational biases.Aims. The OTELO survey aims to provide the deepest narrow-band survey to date in terms of minimum detectable flux and emission line equivalent width in order to detect the faintest extragalactic emission line systems. In this way, OTELO data will complements other broad-band, narrow-band, and spectroscopic surveys.Methods. The red tunable filter of the OSIRIS instrument on the 10.4 m Gran Telescopio Canarias (GTC) is used to scan a spectral window centred at 9175 Å, which is free from strong sky emission lines, with a sampling interval of 6 Å and a bandwidth of 12 Å in the most deeply explored EGS region. Careful data reduction using improved techniques for sky ring subtraction, accurate astrometry, photometric calibration, and source extraction enables us to compile the OTELO catalogue. This catalogue is complemented with ancillary data ranging from deep X-ray to far-infrared, including high resolution HST images, which allow us to segregate the different types of targets, derive precise photometric redshifts, and obtain the morphological classification of the extragalactic objects detected.Results. The OTELO multi-wavelength catalogue contains 11 237 entries and is 50% complete at AB magnitude 26.38. Of these sources, 6600 have photometric redshifts with an uncertaintyδ zphotbetter than 0.2 (1+zphot). A total of 4336 of these sources correspond to preliminary emission line candidates, which are complemented by 81 candidate stars and 483 sources that qualify as absorption line systems. The OTELO survey results will be released to the public on the second half of 2019.
We report on the characterisation of the dust activity and dynamical evolution of two faint active asteroids, P/2019 A4, and P/2021 A5, observed with the 10.4m GTC using both imaging and spectroscopy. Asteroid P/2019 A4 activity is found to be linked to an impulsive event occurring some ±10 days around perihelion, probably due to a collision or a rotational disruption. Its orbit is stable over 100 Myr timescales. Dust tail models reveal a short-term burst producing (2.0±0.7)×10 kg of dust for maximum particle radius rmax=1 cm. The spectrum of P/2019 A4 is featureless, and slightly redder than the Sun. P/2021 A5 was active ∼50 days after perihelion, lasting ∼5 to ∼60 days, and ejecting (8±2)×10 kg of dust for rmax=1 cm. The orbital simulations show that a few percent of dynamical clones of P/2021 A5 are unstable on 20-50 Myr timescales. Thus, P/2021 A5 might be an implanted object from the JFC region or beyond. These facts point to water ice sublimation as the activation mechanism. This object also displays a featureless spectrum, but slightly bluer than the Sun. Nuclei sizes are estimated in the few hundred meters range for both asteroids. Particle ejection speeds (≈0.2 m s−1) are consistent with escape speeds from those small-sized objects.
The OTELO survey is a very deep, blind exploration of a selected region of the Extended Groth Strip and is designed for finding emission-line sources (ELSs). The survey design, observations, data reduction, astrometry, and photometry, as well as the correlation with ancillary data used to obtain a final catalogue, including photo-z estimates and a preliminary selection of ELS, were described in a previous contribution. Here, we aim to determine the main properties and luminosity function (LF) of the [O III] ELS sample of OTELO as a scientific demonstration of its capabilities, advantages, and complementarity with respect to other surveys. The selection and analysis procedures of ELS candidates obtained using tunable filter (TF) pseudo-spectra are described. We performed simulations in the parameter space of the survey to obtain emission-line detection probabilities. Relevant characteristics of [O III] emitters and the LF([O III]), including the main selection biases and uncertainties, are presented. A total of 184 sources were confirmed as [O III] emitters at a mean redshift z=0.83. The minimum detectable line flux and equivalent width (EW) in this ELS sample are $\sim$5 $\times$ 10$^{-19}$ erg s$^{-1}$ cm$^{2}$ and $\sim$6 \AA, respectively. We are able to constrain the faint-end slope ($\alpha = -1.03\pm0.08$) of the observed LF([O III]) at z=0.83. This LF reaches values that are approximately ten times lower than those from other surveys. The vast majority (84\%) of the morphologically classified [O III] ELSs are disc-like sources, and 87\% of this sample is comprised of galaxies with stellar masses of M$_\star$ $<$ 10$^{10}$ M$_{\odot}$.
Aims.Several primitive families in the inner region of the main asteroid belt were identified as potential sources for two near-Earth asteroids (NEAs), (101955) Bennu and (162173) Ryugu, targets of the sample-return missions OSIRIS-REx and Hayabusa2, respectively. Four of the families, located at high proper inclinations (i> 10°), have not yet been compositionally studied: Klio, Chaldaea, Chimaera, and Svea. We want to characterize and analyze these families within the context of our PRIMitive Asteroid Spectroscopic Survey (PRIMASS), in order to complete the puzzle of the origins of the two NEAs.Methods.We obtained visible spectra (0.5–0.9μm) of a total of 73 asteroids within the Klio, Chaldaea, Chimaera, and Svea collisional families, using the instrument OSIRIS at the 10.4 m Gran Telescopio Canarias. We performed a taxonomical classification of these objects, and an analysis of the possible presence of absorption bands related to aqueous alterations, comparing the results with already studied primitive families in the inner main belt.Results.We present here reflectance spectra for 30 asteroids in the Klio family, 15 in Chaldaea, 20 in Chimaera, and 8 in Svea. We show that Klio, Chaldaea, and Chimaera members have moderately red spectral slopes, with aqueous alteration absorption bands centered around 0.7μm, characteristic of the group of primitive families known as Erigone-like. In contrast, Svea shows no 0.7μm features, and neutral and blue spectral slopes, and thus is a Polana-like family. While all four families might be related to (162173) Ryugu, the only family studied in this work that might be related to (101955) Bennu is Svea.
Context. The evolution of galaxies through cosmic time is studied observationally by means of extragalactic surveys. The usefulness of these surveys is greatly improved by increasing the cosmological volume, in either depth or area, and by observing the same targets in different wavelength ranges. A multi-wavelength approach using different observational techniques can compensate for observational biases. Aims. The OTELO survey aims to provide the deepest narrow-band survey to date in terms of minimum detectable flux and emission line equivalent width in order to detect the faintest extragalactic emission line systems. In this way, OTELO data will complements other broad-band, narrow-band, and spectroscopic surveys. Methods. The red tunable filter of the OSIRIS instrument on the 10.4m Gran Telescopio Canarias (GTC) is used to scan a spectral window centred at 9175 angstrom, which is free from strong sky emission lines, with a sampling interval of 6 angstrom and a bandwidth of 12 angstrom in the most deeply explored EGS region. Careful data reduction using improved techniques for sky ring subtraction, accurate astrometry, photometric calibration, and source extraction enables us to compile the OTELO catalogue. This catalogue is complemented with ancillary data ranging from deep X-ray to far-infrared, including high resolution HST images, which allow us to segregate the different types of targets, derive precise photometric redshifts, and obtain the morphological classification of the extragalactic objects detected. Results. The OTELO multi-wavelength catalogue contains 11 237 entries and is 50% complete at AB magnitude 26.38. Of these sources, 6600 have photometric redshifts with an uncertainty delta z(phot) better than 0.2 (1+z(phot)). A total of 4336 of these sources correspond to preliminary emission line candidates, which are complemented by 81 candidate stars and 483 sources that qualify as absorption line systems. The OTELO survey results will be released to the public on the second half of 2019.
Context. Ionized outflows are ubiquitous in non-radio-loud obscured quasars (QSO2s) at different redshifts. However, the actual size of the outflows and their efficiency for gas ejection and star formation truncation are controversial. Large-scale (exceeding several kiloparsec) extended radio structures might be necessary to identify (even to trigger) outflow signatures across such large spatial scales. Aims. We search for large-scale ionized outflows associated with six optically selected QSO2 (five non-radio-loud and one radio-loud) at z ∼ 0.2−0.5, targeting objects with extended radio structures. We also investigate the dynamical state of the QSO2 host galaxies. Methods. We obtained data with the optical imager and long-slit spectrograph (OSIRIS) mounted on the 10.4m Gran Telescopio Canarias Spanish telescope (GTC) for these six QSO2 with the slit located along the radio axis. We traced the gas kinematics with the [OIII]λλ4959,5007 lines to investigate ionized outflows and characterize the dynamical state of the host galaxies. This second study was complemented with previously published spectroscopic data obtained with the multimode focal reducer and low dispersion spectrograph (FORS2) mounted on the Very Large Telescope (VLT) of 13 more QSO2 at similar z. Results. We identify ionized outflows in four out of the six QSO2 observed with the GTC. The outflows are spatially unresolved in two QSO2 and compact in a third (radial size of R = 0.8 ± 0.3 kpc). Of particular interest is the radio-quiet QSO2 SDSS 0741+3020 at z = 0.47. It is associated with a giant ∼112 kpc nebula. An ionized outflow probably induced by the radio structures has been detected along the axis defined by the central ∼1″ radio structure, extending up to at least ∼4 kpc from the active galactic nucleus (AGN). Turbulent gas (σ ∼ 130 km s−1) has also been detected across the giant gas nebula up to ∼40 kpc from the AGN. This turbulence may have been induced by outflows triggered by the interaction between a so-far undetected large-scale radio source and the nebula. Regarding the dynamical state of the host galaxies, we find that the majority of the QSO2 show v/σ < 1, implying that they are dominated by random motions (so-called dispersion-dominated systems). Most (17 of 19) fall in the area of the E/S0 galaxies in the dynamical diagram v/σ versus σ. None are consistent with spiral or disk galaxies.
All stellar-mass black holes have hitherto been identified by X-rays emitted from gas that is accreting onto the black hole from a companion star. These systems are all binaries with a black-hole mass that is less than 30 times that of the Sun1–4. Theory predicts, however, that X-ray-emitting systems form a minority of the total population of star–black-hole binaries5,6. When the black hole is not accreting gas, it can be found through radial-velocity measurements of the motion of the companion star. Here we report radial-velocity measurements taken over two years of the Galactic B-type star, LB-1. We find that the motion of the B star and an accompanying Hα emission line require the presence of a dark companion with a mass of $${68}_{-13}^{+11}$$ solar masses, which can only be a black hole. The long orbital period of 78.9 days shows that this is a wide binary system. Gravitational-wave experiments have detected black holes of similar mass, but the formation of such massive ones in a high-metallicity environment would be extremely challenging within current stellar evolution theories. Radial-velocity measurements of a Galactic B-type star show a dark companion that seems to be a black hole of about 68 solar masses, in a widely spaced binary system.
We report deep spectroscopy of 10 planetary nebulae (PNe) in the Andromeda Galaxy (M31) using the 10.4 m Gran Telescopio Canarias (GTC). Our targets reside in different regions of M31, including halo streams and the dwarf satellite M32, and kinematically deviate from the extended disk. The temperature-sensitive [O iii] λ4363 line is observed in all PNe. For four PNe, the GTC spectra extend beyond 1 μm, enabling the explicit detection of the [S iii] λ6312 and λλ9069, 9531 lines and thus determination of the [S iii] temperature. Abundance ratios are derived and generally consistent with AGB model predictions. Our PNe probably all evolved from low-mass (<2 M☉) stars, as analyzed with the most up-to-date post-AGB evolutionary models, and their main-sequence ages are mostly ∼2–5 Gyr. Compared to the underlying, smooth, metal-poor halo of M31, our targets are uniformly metal rich ([O/H] ≳ −0.4), and seem to resemble the younger population in the stream. We thus speculate that our halo PNe formed in the Giant Stream’s progenitor through extended star formation. Alternatively, they might have formed from the same metal-rich gas as did the outer-disk PNe but were displaced into their present locations as a result of galactic interactions. These interpretations are, although speculative, qualitatively in line with the current picture, as inferred from previous wide-field photometric surveys, that M31's halo is the result of complex interactions and merger processes. The behavior of the N/O of the combined sample of the outer-disk and our halo/substructure PNe signifies that hot bottom burning might actually occur at <3 M☉ but careful assessment is needed.
The low-inclination ( i < 8 ∘ ) primitive asteroid families in the inner main belt, that is, Polana-Eulalia, Erigone, Sulamitis, and Clarissa, are considered to be the most likely sources of near-Earth asteroids (101955) Bennu and (162173) Ryugu. These two primitive NEAs will be visited by NASA OSIRIS-REx and JAXA Hayabusa 2 missions, respectively, with the aim of collecting samples of material from their surfaces and returning them back to Earth. In this context, the PRIMitive Asteroid Spectroscopic Survey (PRIMASS) was born, with the main aim to characterize the possible origins of these NEAs and constrain their dynamical evolution. As part of the PRIMASS survey we have already studied the Polana and Erigone collisional families in previously published works. The main goal of the work presented here is to compositionally characterize the Sulamitis and Clarissa families using visible spectroscopy. We have observed 97 asteroids (64 from Sulamitis and 33 from Clarissa) with the OSIRIS instrument (0.5-0.9 μ m) at the 10.4 m Gran Telescopio Canarias (GTC). We found that about 60% of the sampled asteroids from the Sulamitis family show signs of aqueous alteration on their surfaces. We also found that the majority of the Clarissa members present no signs of hydration. The results obtained here show similarities between Sulamitis-Erigone and Clarissa-Polana collisional families.