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Characterisation of the Warm-Jupiter TOI-1130 system with CHEOPS and photo-dynamical approach
Get PDFAmong the thousands of exoplanets discovered to date, approximately a few
hundred gas giants on short-period orbits are classified as "lonely" and only a
few are in a multi-planet system with a smaller companion on a close orbit. The
processes that formed multi-planet systems hosting gas giants on close orbits
are poorly understood, and only a few examples of this kind of system have been
observed and well characterised. Within the contest of multi-planet system
hosting gas-giant on short orbits, we characterise TOI-1130 system by measuring
masses and orbital parameters. This is a 2-transiting planet system with a
Jupiter-like planet (c) on a 8.35 days orbit and a Neptune-like planet (b) on
an inner (4.07 days) orbit. Both planets show strong anti-correlated transit
timing variations (TTVs). Furthermore, radial velocity (RV) analysis showed an
additional linear trend, a possible hint of a non-transiting candidate planet
on a far outer orbit. Since 2019, extensive transit and radial velocity
observations of the TOI-1130 have been acquired using TESS and various
ground-based facilities. We present a new photo-dynamical analysis of all
available transit and RV data, with the addition of new CHEOPS and ASTEP+ data
that achieve the best precision to date on the planetary radii and masses and
on the timings of each transit. We were able to model interior structure of
planet b constraining the presence of a gaseous envelope of H/He, while it was
not possible to assess the possible water content. Furthermore, we analysed the
resonant state of the two transiting planets, and we found that they lie just
outside the resonant region. This could be the result of the tidal evolution
that the system underwent. We obtained both masses of the planets with a
precision less than 1.5%, and radii with a precision of about 1% and 3% for
planet b and c, respectively
The PEPSI Exoplanet Transit Survey (PETS) -V. New Na D transmission spectra indicate a quieter atmosphere on HD 189733b
Get PDFAbsorption lines from exoplanet atmospheres observed in transmission allow us to study atmospheric characteristics such as winds. We present a new high-resolution transit time-series of HD 189733b, acquired with the PEPSI instrument at the LBT and analyse the transmission spectrum around the Na D lines. We model the spectral signature of the RM-CL V -effect using synthetic PHOENIX spectra based on spherical LTE atmospheric models. We find an Na D absorption signature between the second and third contact but not during the ingress and egress phases, which casts doubt on the planetary origin of the signal. Presupposing a planetary origin of the signal, the results suggest a weak day-to-nightside streaming wind in the order of 0.7 km s-1 and a moderate super-rotational streaming wind in the order of 3-4 km s-1, challenging claims of pre v ailing strong winds on HD 189733b
HIP 41378 observed by CHEOPS: Where is planet d?
Get PDFHIP 41378 d is a long-period planet that has only been observed to transit twice, three years apart, with K2. According to stability considerations and a partial detection of the Rossiter- McLaughlin effect, Pd = 278.36 d has been determined to be the most likely orbital period. We targeted HIP 41378 d with CHEOPS at the predicted transit timing based on Pd = 278.36 d, but the observations show no transit. We find that large (> 22.4 h) transit timing variations (TTVs) could explain this non-detection during the CHEOPS observation window. We also investigated the possibility of an incorrect orbital solution, which would have major implications for our knowledge of this system. If Pd ≠ 278.36 d, the periods that minimize the eccentricity would be 101.22 d and 371.14 d. The shortest orbital period will be tested by TESS, which will observe HIP 41378 in Sector 88 starting in January 2025. Our study shows the importance of a mission like CHEOPS, which today is the only mission able to make long observations (i.e., from space) to track the ephemeris of long-period planets possibly affected by large TTVs
Un tirocinio didattico con “Pianeti in una stanza” per la Notte dei Ricercatori 2024
Get PDFLa collaborazione tra INAF-IAPS e l’Università Roma Tre, consolidata negli anni attraverso eventi pubblici e iniziative educative, ha dato vita a numerosi progetti didattici e divulgativi. Tra questi, spicca l'introduzione nel 2024 di un tirocinio formativo per due studenti del Corso di Laurea Magistrale in Matematica, Curriculum Didattico, in occasione della Notte Europea dei Ricercatori e delle Ricercatrici del 2024, nell'ambito delle attività nella città di Frascati del progetto LEAF (*), organizzato dall'associazione Frascati Scienza.
Il tirocinio ha previsto l'utilizzo di "Pianeti in una stanza", un proiettore sferico low-cost sviluppato dall’associazione Speak Science in collaborazione con INAF-IAPS e l’Università Roma Tre, per coinvolgere il pubblico in attività educative interattive sul Sistema Solare. I tirocinanti hanno organizzato e condotto lezioni e attività divulgative, coinvolgendo 13 classi scolastiche e oltre 2000 partecipanti all'evento pubblico. Il progetto ha rappresentato un’opportunità sperimentale per testare nuovi metodi di divulgazione scientifica e promuovere la partecipazione del pubblico alla ricerca.
(*) Il progetto LEAF è finanziato da HORIZON-MSCA-2023-CITIZENS-01-01 della Commissione Europea, numero Grant Agreement n°101161615, nell’ambito delle azioni Marie Skłodowska-Curie
In ricordo di Tomaso Belloni
Get PDFQuesto volume raccoglie gli interventi che colleghi e amici hanno pronunciato durante la commemorazione per Tomaso Belloni che si è tenuta presso la sede dell’Istituto nazionale di astrofisica a Monte Mario, Roma, il 31 gennaio 2024. È stato pensato per ricordarne la figura, umana e scientifica. È un silenzioso tributo di fronte a un evento tanto inaspettato e che speriamo contribuisca alla sua memoria. Una raccolta di immagini e ricordi, come quelli che chiudono il volume, e che ancora una volta rivelano lo sguardo di Tomaso Belloni
The prototypical major cluster merger Abell 754: I. Calibration of MeerKAT data and radio/X-ray spectral mapping of the cluster
No full textContext. Abell 754 is a rich galaxy cluster at z = 0.0543 and is considered the prototype of a major cluster merger. As many dynamically unrelaxed systems, it hosts diffuse radio emission on megaparsec-scales. Extended synchrotron sources in the intra-cluster medium (ICM) are commonly interpreted as evidence that a fraction of the gravitational energy released during cluster mergers is dissipated into nonthermal components. Aims. Here, we aim to use new MeerKAT UHF- and L-band observations to study nonthermal phenomena in Abell 754. These data are complemented with archival XMM-Newton observations to investigate the resolved spectral properties of both the radio and X-ray cluster emission. Methods. For the first time, we employed the pipeline originally developed to calibrate LOFAR data to MeerKAT observations. This allowed us to perform a direction-dependent calibration and obtain highly sensitive radio images in UHF and L bands that capture the extended emission with unprecedented detail. By using a large XMM-Newton mosaic, we produced thermodynamic maps of the ICM. Results. Our analysis reveals that the radio halo in the cluster center is bounded by the well-known shock in the eastern direction. Furthermore, in the southwest periphery, we discover an extended radio source that we classify as a radio relic that is possibly tracing a shock driven by the squeezed gas compressed by the merger, outflowing in perpendicular directions. The low-luminosity of this relic appears compatible with direct acceleration of thermal pool electrons. We interpret the observed radio and X-ray features in the context of a major cluster merger with a nonzero impact parameter. Conclusions. Abell 754 is a remarkable galaxy cluster showcasing exceptional features associated with the ongoing merger event. The high quality of the new MeerKAT data motivates further work on this system...
Fast supermassive black hole growth in the SPT2349–56 protocluster at z = 4.3
No full textProtoclusters at are gas-rich regions characterized by high
star-formation activity. The same physical properties that enhance star
formation in protoclusters are also thought to boost the growth of SMBHs. We
aim to test this scenario by probing the AGN content of SPT2349-56, a massive,
gas-rich, and highly star-forming protocluster core at discovered as an
overdensity of DSFGs, via Chandra (200 ks) observations, and comparing the
results with the field environment. We detected two protocluster members,
corresponding to an AGN fraction among DSFGs of . This value is
consistent with other protoclusters at , but higher than the AGN
incidence among DSFGs in the field environment. Both AGN are heavily obscured
sources and hosted in star-forming galaxies with
stellar masses. We estimate that the
ISM in the host galaxies can contribute significantly to the nuclear
obscuration. One of the two AGN is highly luminous
() and Compton-thick
(), and likely powered by a
SMBH. Its high accretion rate suggests
that it is in the phase of efficient growth required to explain the presence of
extremely massive SMBHs in the centers of local galaxy clusters. Considering
SPT2349-56 and DRC, a similar protocuster at , we find that gas-rich
protocluster cores at enhance the triggering of luminous
(log) AGN by 3-5 orders of magnitude
with respect to the field environment. Our results indicate that gas-rich
protoclusters at high redshift boost the growth of SMBHs, which will likely
impact the subsequent evolution of the structures, and thus represent key
science targets to obtain a complete understanding of the relation between
environment and galaxy evolution
JOYS+: Mid-infrared detection of gas-phase SO2 emission in a low-mass protostar. The case of NGC 1333 IRAS 2A: Hot core or accretion shock?
No full textContext. Thanks to the Mid-InfraRed Instrument (MIRI) on the James Webb Space Telescope (JWST), our ability to observe the star formation process in the infrared has greatly improved. Due to its unprecedented spatial and spectral resolution and sensitivity in the mid-infrared, JWST/MIRI can see through highly extincted protostellar envelopes and probe the warm inner regions. An abundant molecule in these warm inner regions is SO2, which is a common tracer of both outflow and accretion shocks as well as hot core chemistry. Aims. This paper presents the first mid-infrared detection of gaseous SO2 emission in an embedded low-mass protostellar system rich in complex molecules and aims to determine the physical origin of the SO2 emission. Methods. JWST/MIRI observations taken with the Medium Resolution Spectrometer (MRS) of the low-mass protostellar binary NGC 1333 IRAS 2A in the JWST Observations of Young protoStars (JOYS+) program are presented. The observations reveal emission from the SO2 ν3 asymmetric stretching mode at 7.35 µm. Using simple slab models and assuming local thermodynamic equilibrium (LTE), we derived the rotational temperature and total number of SO2 molecules. We then compared the results to those derived from high-angular-resolution SO2 data on the same scales (∼50−100 au) obtained with the Atacama Large Millimeter/submillimeter Array (ALMA). Results. The SO2 emission from the ν3 band is predominantly located on ∼50−100 au scales around the mid-infrared continuum peak of the main component of the binary, IRAS 2A1. A rotational temperature of 92 ± 8 K is derived from the ν3 lines. This is in good agreement with the rotational temperature derived from pure rotational lines in the vibrational ground state (i.e., ν = 0) with ALMA (104 ± 5 K), which are extended over similar scales. However, the emission of the ν3 lines in the MIRI-MRS spectrum is not in LTE given that the total number of molecules predicted by a LTE model is found to be a factor of 2 × 104 higher than what is derived for the ν = 0 state from the ALMA data. This difference can be explained by a vibrational temperature that is ∼100 K higher than the derived rotational temperature of the ν = 0 state: Tvib ∼ 200 K versus Trot = 104 ± 5 K. The brightness temperature derived from the continuum around the ν3 band (∼7.35 µm) of SO2 is ∼180 K, which confirms that the ν3 = 1 level is not collisionally populated but rather infrared-pumped by scattered radiation. This is also consistent with the non-detection of the ν2 bending mode at 18−20 µm. The similar rotational temperature derived from the MIRI-MRS and ALMA data implies that they are in fact tracing the same molecular gas. The inferred abundance of SO2 , determined using the LTE fit to the lines of the vibrational ground state in the ALMA data, is 1.0 ± 0.3 × 10−8 with respect to H2, which is on the lower side compared to interstellar and cometary ices (10−8−10−7). Conclusions. Given the rotational temperature, the extent of the emission (∼100 au in radius), and the narrow line widths in the ALMA data (∼3.5 km s−1), the SO2 in IRAS 2A likely originates from ice sublimation in the central hot core around the protostar rather than from an accretion shock at the disk–envelope boundary. Furthermore, this paper shows the importance of radiative pumping and of combining JWST observations with those from millimeter interferometers such as ALMA to probe the physics on disk scales and to infer molecular abundances
The X-ray enhancements of radio-loud quasars at high redshift: new results at z = 4–7
No full textHighly radio-loud quasars (HRLQs; log R > 2.5) at z ≿ 4 show apparent enhanced X-ray emission compared to matched HRLQs at lower redshifts, perhaps due to a redshift-dependent fractional contribution to the X-ray luminosity from inverse-Compton scattering of cosmic microwave background photons (IC/CMB). Using new Chandra observations and archival X-ray data, we investigate this phenomenon with an optically flux-limited sample of 41 HRLQs at z = 4–5.5 all with sensitive X-ray coverage, the largest sample utilized to date by a wide margin. X-ray enhancements are assessed using X-ray-to-optical flux ratios and spectral energy distributions. We confirm the presence of X-ray enhancements at a 4.9–5.3σ significance level, finding that the median factor of enhancement is ≈1.8 at our sample median redshift of z ≈ 4.4. Under a fractional IC/CMB model, the expected enhancement at lower redshifts is modest; e.g. ≈4 per cent at z ≈ 1.5. We also investigate a sample of seven radio-loud quasars (RLQs; log R > 1) at even higher redshifts of z = 5.6–6.8, using new and archival X-ray data. These RLQs also show evidence for X-ray enhancements by a median factor of ≈2.7 at a 3.7–4.9σ significance level. The X-ray spectral and other properties of these z = 5.6–6.8 RLQs, however, pose challenges for a straightforward fractional IC/CMB interpretation of their enhancements
Investigating the interplay between the coronal properties and the hard X-ray variability of active galactic nuclei with NuSTAR
No full textActive galactic nuclei (AGN) are extremely variable in the X-ray band down to very short timescales. However, the driver behind the X-ray variability is still poorly understood. Previous results suggest that the hot corona responsible for the primary Comptonized emission observed in AGN is expected to play an important role in driving the X-ray variability. In this work, we investigate the connection between the X-ray amplitude variability and the coronal physical parameters; namely, the temperature (kT) and optical depth (τ). We present the spectral and timing analysis of 46 NuSTAR observations corresponding to a sample of 20 AGN. For each source, we derived the coronal temperature and optical depth through X-ray spectroscopy and computed the normalized excess variance for different energy bands on a timescale of 10 ks. We find a strong inverse correlation between kT and τ, with correlation coefficient of r < -0.9 and negligible null probability. No clear dependence was found among the temperature and physical properties, such as the black hole mass or the Eddington ratio. We also see that the observed X-ray variability is not correlated with either the coronal temperature or optical depth under the thermal equilibrium assumption, whereas it is anticorrelated with the black hole mass. These results can be interpreted through a scenario where the observed X-ray variability could primarily be driven by variations in the coronal physical properties on a timescale of less than 10 ks; whereas we assume thermal equilibrium on such timescales in this work, given the capability of the currently available hard X-ray telescopes. Alternatively, it is also possible that the X-ray variability is mostly driven by the absolute size of the corona, which depends on the supermassive black hole mass, rather than resulting from any of its physical properties