Black hole mass and accretion rate are two key parameters that define active galactic nuclei (AGN) and some characteristics are pronounced when observed in X-ray. For example, rapid X-ray variability tends to be observed in systems with smaller black holes. The shape of the wide-band spectral energy distribution (SED) appears to be controlled by an accretion rate: the fraction of energy emitted in X-ray relative to the total energy output varies according to the accretion rate. These are well known facts but there are some exceptional objects.
Astrophysics and Space Science
Photsat is the first astrophysics observatory being prepared by the Institut d'Estudis Espacials de Catalunya (IEEC) to be allocated in a cubesat mission to be launched in 2027-2028. The mission aims to survey the full sky during 2-3 years, obtaining photometric lightcurves for V<12-15 mag in several photometric filters, covering the optical and the ultraviolet range with a cadence of one datapoint every 2 days. This will complement the information of the transient sky at the bright end that other projects, as LSST, are not able to provide.
GMV offers the opportunity to participate in a remunerated project for the Final Master's Thesis (TFM). The increasing density of satellites and space debris in Earth's orbit poses significant challenges for space operations and safety. Traditional ground-based observation methods have limitations in detecting small-sized debris, especially those smaller than 10cm.
Supermassive black holes (SMBHs) reside at the centres of most massive galaxies, where they grow by accreting matter from their surroundings. During periods of intense accretion, they become active and release vast amounts of energy that can regulate the star formation of their host galaxies. Despite their fundamental role in galaxy evolution, the mechanisms that fuel SMBH activity are not yet fully understood, as the material feeding the black hole must be transported from galactic or even larger scales down to the central parsec of the galaxy.
A diversity of physical experiments are trying to detect dark matter in theMilky Way in physical experiments in the Earth, assuming dark matter is made ofweakly interacting fields. In the case of haloscopes, dark matter is assumed tobe the QCD axion which, in the presence of a strong magnetic field, converts toa photon with energy equal to the total axion energy (rest mass plus kineticenergy). Therefore, the spectral line shape observed for the created photonsdepends on the velocity distribution of the dark matter in the laboratory frameof the experiment.
In this project, the student will assemble a low-cost radio telescope (a Horn antenna) on the roof of the Physics Faculty building, for future courses in radio astronomy at UB. This telescope is tailored to observe in the protected frequency band containing the HI emission line at 1.42GHz.
There are a few planetary systems already observed with JWST transmission spectra, such as TRAPPIST-1, and K2-18. As can be seen in [1,2], stellar activity (flares in particular) is the key limitation to measuring exoatmospheres of planets orbiting M dwarfs (e.g. TRAPPIST-1). This is also shown in [3].
There has been some controversy in the community when attributing signal excursions in planetary transits either to flares or starspots signatures. See for example the assigned starspot apparently mistaken in [4], which is summarized in [5].
Mars is known to have a very thin atmosphere and almost no magnetosphere.
Some of the observations have revealed the presence of greenhouse gases, such as
CH4, in the Martian atmosphere, and in a very few times although controversially,
on the surface. An example of this controversy can be found in the Curiosity CH4
surface detection [1], but not confirmed by ESA's Mars orbiters [2].
Observations of the Martian atmosphere (and its composition) taken by orbiters,
landers, and rovers are often taken to feed the models that describe exoplanets
Transient sources in the high energy (HE, GeV) and very-high energy (VHE, TeV) gamma-ray domain have turned out to be excellent laboratories to test particle acceleration, emission, and absorption processes under extreme conditions, thanks to the multiple discoveries of transient phenomena at GeV and TeV energies reported during the last decade [1].
A leading candidate to explain the existence of dark matter in the Universe is the axion, which is detectable in experiments that use resonant cavities embedded in a strong magnetic field to turn an ambient axion of the dark matter halo of the Milky Way into a resonant photon. Superconducting qubits can be used to detect these photons without absorbing them, allowing for multiple detections of the same photon with minimal noise at mK temperatures, as demonstrated by Dixit et al. 2019.