I will provide a general overview of the current status of the NOT as for operations, and the plans for the near future.
The design, projected performance and status of NTE (NOT Transient Explorer) is described. NTE is in reality three independent instruments mounted together at the Cassegrain focus of the NOT: NTE-VIS-imager, NTE-IR-imager and NTE-spectrograph. The two imagers can be used in parallel via a dichroic and provides a FoV of 6' with a sampling of 0.18"/pix. They are in performance very similar to...
I will describe The NOT Transient Explorer (NTE). NTE is designed to be an instrument that can be permanently mounted (together with FIES) at the NOT where it will allow the NOT to be a powerful facility for follow-up observations of transient sources like supernovae, kilo novae end afterglows of gamma-ray bursts. In addition the instrument should provide capabilities requested from other the...
Special narrow band spectroscopic observations with ~10nm band widths centered at wavelengths 672nm, 770nm, 870nm and 1050nm with resolution of R~4000 are presented along conclusions on how the night sky brightness affects potential future extremely large telescope (ELT) spectrograph designs . The presented observations are less prone to be contaminated by bright hydroxyl (OH) emission lines...
FastCam is an instrument designed to obtain high spatial resolution images in the optical wavelength range from ground-based telescopes by using the Lucky Imaging technique. This technique is based on the idea of registering the instants of atmospheric stability, typically lasting just some milliseconds, using very short exposures. The instrument consists of a very low noise and very fast...
We describe the future potential of multiwavelength polarimetric observations of natural near-Earth objects (NEOs) and artificial space-debris objects (SDs) at the Nordic Optical Telescope (NOT). Together with state-of-the-art theoretical modeling based on the first principles of physics, the forthcoming NOT observations promise to be a game-changer in the physical characterization of NEOs and...
Quasars are manifestations of accreting supermassive blackholes in the centers of galaxies. It is currently uncertain how many quasars there are as quasar selection is known to be biased and incomplete. In this work we try to use novel more unbiased quasar selection techniques to reach a more reliable and complete census of quasars in a large section of the sky.
Unravelling the age is one of the most challenging tasks since most are subject to significant uncertainties, and their determinations face multiple observational and theoretical challenges. Ages are generally better determined in stellar associations. They usually provide a significant sample of objects when testing the hypothesis that they were born simultaneously from the same molecular...
Supernova research is one of the transient sciences for which the flexible NOT has had significant impact. I will present on the efforts from our Stockholm supernova group over the past 25+ years, mostly focusing on the more recent Zwicky Transient Facility era, but also on ideas for follow-up of LSST targets.
The Nordic-optical-telescope Un-biased Transient Survey, aka NUTS, is a diverse collaboration of researchers spread across several Nordic and other European countries. The common goal of our group is to engage in cutting-edge transient science and research training with the NOT. Over the past six years, NUTS has obtained extensive data sets of a multitude of transients including all flavours...
The Young Supernova Experiment (YSE) is a wide-field, multiband (griz) survey using the Pan-STARRS telescopes with a unique synergistic observing strategy. YSE is able to identify the youngest transients within days and even hours of first explosion. Our large followup programme with the NOT plays a pivotal role in the classification and and followup of YSE transients. I will demonstrate how...
In this talk, I will present the spectroscopic and photometric evolution of a sample of supernovae (SNe) observed with the Nordic Optical Telescope (NOT) between 2018 and 2022. This sample includes a few hydrogen-rich SNe located in low-luminosity host galaxies, a peculiar hydrogen-poor SN (SN~Ic) and one superluminous SN. I will also discuss the properties we can infer from the observations...
The NOT has a long tradition in the follow-up of gamma-ray bursts, starting with observations of the very first afterglow back in 1997. Focus has been both on the physics of these events and their use as probes of the distant universe. Twenty-five years later, the NOT has become a major worldwide contributor to this field. Starting in 2017, the parallel branch of gravitational wave sources has...
SN 2020lao is a fast Type Ic-BL SN, without an associated GRB, which was nevertheless discovered within 2.5 hours of explosion by ZTF. Fortuitously, TESS also captured its rise with a 30 minute cadence. Our follow-up comprising of optical spectra and multi-band light curves commenced within 24 hours of explosion. Due to disruption from the pandemic, we had to hop between a wide range of...
We are currently performing a Type Ia supernova (SN Ia) near-infrared (NIR) imaging survey in J- and H-bands at NOT, which combined with the FLOWS project efforts of building a sample of 10^3 SNe Ia observed in the NIR, will demonstrate the ability to get systematics-limited (better than 3%) distances with minimal resources, and expand our view of Laniakea out to z=0.1. Our planned analysis...
The possibility to observe Classical (and recurrent) novae at high spectral resolution has allowed a more deep understanding of the nova phenomenon, with the discovery of 1) THEA lines; 2) lithium in their ejecta; and 3) the presence of multiple components, whose evolution is simultaneous to the high-energy (GeV) emission detected from space-based missions. In this talk, I will give a short...
Telescopes of the 2-4 meter class such as the NOT can be an extremely important observational asset for the field of small solar system objects, thanks to a combination of large aperture and typically easier access compared to 8-10 meter class instruments, especially on short notice.
At the same time, the field of small bodies is characterized by the more rapid timescales on which objects...
Comets and asteroids are remnants of the solar system’s original planetesimals, and act as probes of the environment where they formed. The ice-rich comets formed beyond the snow line, while asteroids accreted inside it. Both provide information about conditions in the protoplanetary disk, but at different radial distances. The newly discovered class of "active asteroids" blurs this...
Tracking and characterisation of near-Earth objects (NEOs) are crucial aspects of planetary science by helping us to understand the formation and evolution of Solar System, and planetary defence by providing information required for impact risk mitigation strategies. As more NEOs get discovered, also the opportunities to characterise them better increase, including using the Nordic Optical...
Space exploration missions to small-bodies such as asteroids and comets typically require observational support from extensive campaigns by ground-based and Earth-orbiting facilities. These observing campaigns are necessary both for optimizing mission and instrument design and for maximizing the scientific return of a mission. In some extreme cases the mission goals cannot be met without...
Tracking of artificial objects in orbit around Earth (for example satellites and discarded rocket bodies), as well as characterisation of capabilities, ownership, and operational status is an integral part of space situational awareness. This activity is becoming increasingly important as space gets more congested, but it also has relevant implications in other areas, such as policy making,...
In the Solar System, planetary orbits are nearly circular, coplanar, and their planes are only tilted by $7^\circ$ relative to the Sun's equator. It is neatly ordered with four rocky planets within 2~au, while four gas giants orbit at much larger separations. This regularity formed the blueprint of planetary formation, where planets form in the spinning protoplanetary disk resulting in...
A new mirror-slicer optical instrument, named MAAT, will allow the OSIRIS spectrograph on the Gran Telescopio de CANARIAS (GTC) the capability to perform Integral-Field Spectroscopy over a seeing-limited FoV 12.0” × 8.5" with a slice width of 0.303". MAAT will enhance the resolution power of OSIRIS by 1.6 times as compared to its 0.6" long-slit. All the eleven OSIRIS grisms and volume-phase...
We present the results of a recent study of the Algol-type eclipsing binary system AS Eri based on the combination of the MOST and TESS light curves as well as a collection of very precise radial velocities obtained with the spectrographs HERMES operating at the Mercator telescope, La Palma, and TCES operating at the Alfred Jensch telescope, Tautenburg. The primary component is a known A3...
The role of different processes in shaping of planetary nebula (PN) around post-AGB stars is not fully understood. Recently, binary interactions have been thought of as the main shapers of PN; however, multiple studies seem to suggest that the role of companions might be overestimated or even question current post-AGB star evolutionary models. It is possible that an intrinsic change in nature...
I demonstrate the continued strength of FIES in studies of stellar evolution involving eclipsing binary stars and star clusters.
We present the preliminary results, accurate measurements
and long term monitoring,
of our on-going programme to
extend the list of well observed polarimetric standard stars.
Many of the current polarimetry standard star catalogues
have mainly
very bright (V< 9mag) stars which are not well observed
and sky coverage is very sparse
ESO presented a list of fainter standard stars,...
Type Ia supernovae (SNe Ia) are among the best standard candles for obtaining an accurate measurement of the Hubble constant (H0) in late times and can help us shed light on the apparent discrepancy with the estimated value in the opposite edge of the universe, early times. This may indicate additional new physics beyond the standard cosmological model or significant systematic errors in the...
The NOT was approached by Graphic Storytelling students from VIA University College in Viborg, Denmark, to work on an Applied Comics collaboration. Applied Comics are a powerful tool to communicate factual information to all target audiences. In their collaboration with the NOT, the students developed comics about various NOT-related subjects, with the intent of informing people of some of the...
DiPol-UF is a new instrument capable of high precision (10−5) polarimetric observations simultaneously in three passbands (BVR). The instrument utilizes electron-multiplied EM CCD cameras for high efficiency and fast image readout. The key features of DiPol-UF are: (i) optical design with high throughput and inherent stability; (ii) great versatility which makes the instrument optimally...
Throughout its operation the NOT has offered a valuable resource for studying the spot coverage and surface magnetic fields of late-type active stars. Such stellar surface maps can be constructed from high resolution spectroscopy and spectropolarimetry using the Doppler imaging and Zeeman Doppler imaging methods. These methods provide a uniquely detailed look at the stellar dynamo generated...
Late O or early B stars showing Balmer lines in emission and infrared excess are classified as Be stars. Both, the emission in Balmer lines and the infrared excess, have their origin in a circumstelar disk-alike decretion sctructure. Rapid rotation and pulsations are known to be part of the mechanism of formation of such a structure but the process is still unknown. Be stars are also known to...
Yellow hypergiant stars are objects of great interest because they are in an extreme transition phase of evolution, in which the stars have dynamically unstable atmospheres and undergo recurring mass loss outbursts. As post-red supergiants, they are a possible bridge in the evolutionary gap between red supergiant and B[e] supergiant or luminous blue variable phases. On the Hertzsprung-Russell...
NOT has been an important telescope in studying galactic nebulae and stellar outflows since its inauguration more than 30 years ago. Superb observational capabilities provide simultaneous imaging and 2D spectral data, which is indispensable when investigating occasionally rapidly evolving stellar ejecta. In this talk I will provide an overview of various types of stellar outflows within my...
Stellar archaeology seeks to use information gathered from old, metal-poor stars (pop II stars) in the Milky Way and its satellites to place constraints on the first generation of stars to form in the Universe (pop III stars), which we can no longer directly observe. I will present the results of two observing campaigns carried out with the NOT (and other similar sized telescopes). The first...
In the panorama of Galactic astronomy, the characterization of Milky Way stellar populations and chemical abundances is of crucial importance for revealing the structure and evolution of the Galaxy. For this reason, hundreds of thousands of spectra have already been obtained by high resolution spectroscopic surveys, and the main challenge for building an accurate picture is the homogenization...
Carbon and nitrogen abundances are among most useful quantitative indicators of mixing processes in evolved stars. Because of the first dredge-up abundances of 12^C decrease while abundances of 13^C and 14^N increase. These alterations become efficient again on the red giant branch when stars reach the so-called luminosity bump, and depend on stellar evolutionary stage, mass, metallicity,...
The Alhambra Faint Object Spectrograph and Camera, ALFOSC, is provided by the Instituto de Astrofisica de Andalucia (IAA) under a joint agreement with the University of Copenhagen and NOT. With a field of view of 6.4 x 6.4 arcminutes in imaging mode, it can also be used for low/medium resolution spectroscopy, and polarimetry. In this talk I will present a selection of scientific results to...
In this talk I will review some of the major scientific highlights produced in the past decade by Instituto de Astrofisica de Canarias (IAC) researchers using the Nordic Optical Telescope. I will present their main scientific lines of research and potential future areas of development for the telescope from the IAC perspective.
Open clusters are ideal laboratories to investigate a variety of astrophysical topics, from stellar physics to galaxy disk evolution. The Gaia mission and the complementary, ground-based massive spectroscopic surveys have led to a revolution in our knowledge of the Milky Way and its companion dwarfs galaxies including, of course, open clusters. However, they need complementary observations...
IACOB is an ambitious long-term observational project which is contributing to the new era of investigation of massive stars by concentrating on Galactic OB stars. More specifically, the main scientific goal of the IACOB project is to provide a complete empirical overview of the physical properties of a statistically significant sample of OB stars. In particular, the ultimate driver of the...
Active galactic nuclei with jets are the most persistently bright objects in the observable Universe. A subclass called blazars, whose jets are oriented within a few degrees of the Earth’s line of sight, are the most extreme particle accelerators observed across the electromagnetic spectrum. For over 30 years the Nordic Optical Telescope has played a vital role in the multimessenger studies of...
Outflows play a major role in the evolution of galaxies and are said to be ubiquitous within the Active Galactic Nuclei (AGNs) population. However, we are far from having a complete picture of their properties, specially considering their impact on the evolution of Low-Ionisation Nuclear Emission-line Regions (LINERs).
Although resolved kinematic information has proven to be crucial for the...
We present preliminary results from our on-going NOT programme
"Changing State QSO's: a clue to understand their physics".
Extreme photometric variations in
AGN's are often accompanied by large spectral changes whose origin
is not yet understood. This includes Changing Look or Changing State Quasars
(changes in the BLR), candidate Tidal Disruption Events, Erratic Blazar
Variability....
The study of tidal disruption events (TDEs) presents a new opportunity to investigate the nuclear regions of galaxies and the supermassive black holes (SMBHs) therein. The luminous outburst produced by the accretion of a star onto a SMBH heats nearby interstellar dust, which then re-radiates this energy producing a so-called infrared (IR) echo. Observations of IR echoes, and the outbursts...
$\hspace{3pt}$ AT2020wey is a member of the growing class of “faint and fast” tidal disruption events (TDEs) (peak blackbody luminosity $\log{(L/erg\,s^{-1})} <43.5$ and exponential rise time $t_r < 20d$) and it shows the fastest decline in the UV from any other TDE to date. Critical spectroscopic observations were performed with the NOT in order to reveal that it is part of the Hydrogen TDE...
Supermassive black holes have been known to disrupt passing stars producing outbursts called tidal disruption events (TDEs) offering a unique view on the early stages of the accretion disk and jet formation. The advent of large-scale optical time-domain surveys has significantly increased the number of known events and challenged our understanding of their dynamics and emission processes....
The measured Hubble constant between cosmological probes in the early or late universe are different. This may be real, with profound implications for physics, or due to observational flukes. Measuring the Time Delays between strongly lensed images of quasars or supernovae provides a single-step measurement of H0 in the late universe, fully independent of any other cosmological probe. This...
Thanks to the accurate astrometry and kinematics provided by the Gaia mission the complex formation process of the Milky Way is now being understood. The halo of the Milky Way has suffered from the continued merging process with dwarf and primitive satellites. Luckily, a substructure originating in a single accretion event can be identified as a tight cluster of stars in phase space sharing...
We will present a series of seven Python Jupyter Notebooks designed to teach master-level students the basic steps of data reduction for observations with the Alhambra Faint Object Spectrograph and Camera (ALFOSC). This pedagogical tool, which translates IRAF tasks into the widespread Python language, has been successfully deployed for the course “Observational Astrophysics II” at the...
I will give an overview of the educational use of the NOT.
Since 2007 we held summer schools with students from Copenhagen University and lately with students from (almost) all Danish Universities. The purpose is twofold. Primarily, the objective is to give the students hands-on experience with astrophysical observations in all aspects, i.e.,proposal-writing, planning, execution, analysis and presentation. The projects have included exoplanet...
A national hands-on course on observational astronomy has been organised annually by the University of Turku since 2013 to carry out remote observations with the NOT from the Tuorla observatory. Typically, the course has had around 20 MSc/PhD students, who come from all the four Finnish universities that teach astronomy (Turku, Helsinki, Oulu, and Aalto). The students are divided into research...
Observing with the Nordic Optical Telescope has, for many years, been an integral part of the course Observational Astrophysics II (ObsII) offered to masters and PhD students at Stockholm University. I will review the activities related to the course in Stockholm, which also includes observations with the 20m radio telescope at the Onsala Space Observatory.
I will present a new course on observational astrophysics offered since the spring of 2022 at the Norwegian University of Science and Technology in Trondheim, Norway. The course is mainly aimed at 3d-4th year students of the BSc-MSC program in Physics and includes lectures, data analysis "AstroLAB" sessions and an observing project with the Nordic Optical Telescope. In this project the...
Since the beginning of the NOT operations in 1990 we have had students working as an integral part of the operational staff at the telescope. When Johannes Andersen was the NOT director he expanded the size of the NOT student program to the present size with 5-6 students at any given time. Studentships at NOT are typically one year in length. In the era of large telescopes, it makes good sense...
