The terahertz (THz) region of the electromagnetic spectrum is of great importance for astrophysics. In fact, it is central to the whole field of experimental cosmology. This paper outlines the range of astrophysical problems that can be answered by observing at THz frequencies, describes some of the major THz astronomical telescopes that are being constructed, and gives a vision of the way in w...

This paper proposes a reduction-segmentation scheme for radioastronomical cubes. In order to avoid the curse of dimensionality phenomenon, a reduction technique is proposed as preprocessing step before classification. On each site of the image a spectrum is observed, exhibiting few spectral rays, modeled as a weighted mixture of selected Gaussian functions. These weights feed a Hierarchical Mar...

ASTRON is building the world’s largest radio telescope for low frequencies, LOFAR. LOFAR is optimized for detecting astronomical signals in the 30-80 MHz and 120-240 MHz frequency windows. Since this part of the spectrum is in extensive use by others, a special RFI mitigation strategy is implemented which will be described in the paper. International RFI measurements will be presented and we wi...

I Zwicky 1 (I Zw 1) is the prototype narrow line quasar. Its narrow line profiles minimize blending effects and thus allow a significantly more accurate study of individual quasar emission lines. We report here the results of our study of the 1150-3250 Å emission of I Zw 1 using a high S/N (50-120) spectrum obtained with the Faint Object Spectrograph (FOS) of the Hubble Space Telescope (HST). T...

The Virtual Observatory (VO) for Astronomy is a framework that empowers astronomical research by providing standard methods to find, access, and utilize astronomical data archives distributed around the world. VO projects in the world have been strenuously developing VO software tools and/or portal systems. Interoperability among VO projects has been achieved with the VO standard protocols defi...

We present accurate measurements of the central wavelengths of 4947 atomic absorption lines in the solar optical spectrum. The wavelengths, precise to a level ∼ 50 − 150 m s −1 , are given for both flux and disc-centre spectra, as measured in relatively recent FTS solar atlases. This catalogue modernizes existing sources based on photographic measurements and provides a benchmark to test and pe...

Spectroscopy of the ν1 band of the astrophysically relevant ion HCO(+) is performed with an optical parametric oscillator calibrated with an optical frequency comb. The sub-MHz accuracy of this technique was confirmed by performing a combination differences analysis with the acquired rovibrational data and comparing the results to known ground-state rotational transitions. A similar combination...

The Oriented Scintillation Spectrometer Experiment on the COMPTON Observatory was designed to undertake a broad range of high energy astronomical observations. Many of these have been realized during the first three years of the mission. In this paper we present several of the recent results from OSSE. We highlight recent OSSE results on the galactic center region and on transient galactic X-ra...