F. Tercero

Yebes Observatory

Author Statistics

Papers

Citation

H-Index

i-10 index

Research Trends

Author Order

Document Type

Co-Authors

J. A. López-Pérez

Yebes Observatory

J. D. Gallego

Yebes Observatory

P. de Vicente

Yebes Observatory

J. Cernicharo

Consejo Superior de Investigaciones Científicas

J. A. López-Fernández

Yebes Observatory

Luis Enrique García-Muñoz

Universidad Carlos III de Madrid

J. R. Pardo

Instituto de Física Fundamental

J. A. López Fernández

Yebes Observatory

C. Cabezas

Instituto de Física Fundamental

ÓG

Ó. García-Pérez

Yebes Observatory

Cooperative Institutions

Yebes Observatory

Instituto Geográfico Nacional

Consejo Superior de Investigaciones Científicas

Spanish National Observatory

Instituto de Física Fundamental

Ministerio de Transportes, Movilidad y Agenda Urbana

Universidad Politécnica de Madrid

Centre National de la Recherche Scientifique

Instituto de Ciencia de Materiales de Madrid

Institut de Radioastronomie Millimétrique

Author Statistics

Papers

Citation

H-Index

i-10 index

Research Field

Discovery of allenyl acetylene, H₂CCCHCCH, in TMC-1

Astronomy and Astrophysics (2021)

J. Cernicharo C. Cabezas M. Agúndez B. Tercero N. Marcelino

We present the discovery in TMC-1 of allenyl acetylene, H

Acetylene

10.1051/0004-6361/202140482

Cite

Citations (36)

Implementation of a quasioptical system for free-space measurements: applications to radio astronomy

Ó. García-Pérez F. Tercero S. López-Ruiz B. Vaquero J. M. Serna

Radio Astronomy

Very-long-baseline interferometry

Free space

Space research

10.1049/cp.2017.0269

Cite

Citations (0)

Ultra-deep 31.0–50.3 GHz spectral survey of IRC+10216

Astronomy and Astrophysics (2021)

J. R. Pardo J. Cernicharo B. Tercero C. Cabezas Celina Bermúdez

Context. IRC+10216, the carbon-rich envelope of the asymptotic giant branch (AGB) star CW Leo, is one of the richest molecular sources in the sky. Available spectral surveys below 51 GHz are more than 25 years old and new work is needed. Aims. Characterizing the rich molecular content of this source, specially for heavy species, requires to carry out very sensitive spectral surveys at low frequencies. In particular in this work we have achieved an rms in the range 0.2-0.6 mK per MHz. Methods. long Q-band (31.0-50.3 GHz) single dish integrations were carried out with the Yebes 40m telescope using specifically built receivers. State of the art line catalogs are used for line identification. Results. A total of 652 spectral features corresponding to 713 transitions from 81 species (we count as different the isomers, isotopologues and ortho/para species) are present in the data. Only 57 unidentified lines remain with signal to noise ratios >3. Some new species and/or vibrational modes have been discovered for the first time with this survey. Conclusions. This IRC+10216 spectral survey is, by far, the most sensitive one carried out to this date in the Q-band. It therefore provides the most complete view of IRC+10216 from 31.0 to 50.3 GHz, giving unique information on its molecular content, specially for heavy species. Rotational diagrams built from the data provide valuable information on the physical conditions and chemical content of this circumstellar envelope.

Isotopologue

Asymptotic giant branch

Circumstellar envelope

Carbon star

Spectral resolution

10.1051/0004-6361/202142263

Cite

Citations (22)

²⁸SiOv= 0J= 1–0 emission from evolved stars

Astronomy and Astrophysics (2016)

P. de Vicente V. Bujarrabal A. Díaz-Pulido C. Albo J. Alcolea

Observations of 28SiO v=0 J=1-0 line emission (7-mm wavelength) from AGB stars show in some cases peculiar profiles, composed of a central intense component plus a wider plateau. Very similar profiles have been observed in CO lines from some AGB stars and most post-AGB nebulae and, in these cases, they are clearly associated with the presence of conspicuous axial symmetry and bipolar dynamics. We present systematic observations of 28SiO v=0 J=1-0 emission in 28 evolved stars, performed with the 40~m radio telescope of the IGN in Yebes, Spain. We find that the composite core plus plateau profiles are almost always present in O-rich Miras, OH/IR stars, and red supergiants. They are also found in one S-type Mira ($\chi$ Cyg), as well as in two semiregular variables (X Her and RS Cnc) that are known to show axial symmetry. In the other objects, the profiles are simpler and similar to those of other molecular lines. The composite structure appears in the objects in which SiO emission is thought to come from the very inner circumstellar layers, prior to dust formation. The central spectral feature is found to be systematically composed of a number of narrow spikes, except for X Her and RS Cnc, in which it shows a smooth shape that is very similar to that observed in CO emission. These spikes show a significant (and mostly chaotic) time variation, while in all cases the smooth components remain constant within the uncertainties. The profile shape could come from the superposition of standard wide profiles and a group of weak maser spikes. Alternatively, we speculate that the very similar profiles detected in objects that are axisymmetric may be indicative of the systematic presence of a significant axial symmetry in the very inner circumstellar shells around AGB stars; the presence of such symmetry would be independent of the probable weak maser effects in the central spikes.

Asymptotic giant branch

Line (geometry)

10.1051/0004-6361/201527174

Cite

Citations (17)

Analysis of the defocused Gaussian beam telescope on Cassegrain feeds

Microwave and Optical Technology Letters (2002)

Luis Enrique García-Muñoz J. A. López Fernández Leandro de Haro Ariet F. Tercero Belén Galocha Iragüen

Abstract Defocused Gaussian beam telescope geometry and its tolerance with the changes in the values of their lenses and focalization distances are analyzed. The Gaussian beam telescope is very useful in systems that must operate over broad bandwidths. This device has particularly functional properties in Cassegrain radiotelescope feed systems. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 32: 420–423, 2002.

Cassegrain reflector

Gaussian beam

Focalization

10.1002/mop.10196

Cite

Citations (9)

A Tri-band Low-noise Cryogenic Receiver for Geodetic VLBI Observations with VGOS Radio Telescopes

J. A. López-Pérez F. Tercero J. M. Serna-Puente Beatriz Vaquero-Jiménez M. Patino-Esteban

This paper shows the development of a simultaneous tri-band (S: 2.2 - 2.7 GHz, X: 7.5 - 9 GHz and Ka: 28 - 33 GHz) low-noise cryogenic receiver for geodetic Very Long Baseline Interferometry (geo-VLBI) which has been developed by the technical staff of Yebes Observatory (IGN) laboratories in Spain. The receiver was installed in the first radio telescope of the Red Atlántica de Estaciones Geodinámicas y Espaciales (RAEGE) project, which is located in Yebes Observatory, in the frame of the VLBI Global Observing System (VGOS). After this, the receiver was borrowed by the Norwegian Mapping Autorithy (NMA) for the commissioning of two VGOS radiotelescopes in Svalbard (Norway). A second identical receiver was built for the Ishioka VGOS station of the Geospatial Information Authority (GSI) of Japan, and a third one for the second RAEGE VGOS station, located in Santa María (Açores Archipelago, Portugal). The average receiver noise temperatures are 21, 23 and 25 Kelvin and the measured antenna efficiencies are 70%, 75% and 60% in S-band, X-band and Ka-band, respectively.

Very-long-baseline interferometry

10.20944/preprints201912.0408.v1

Cite

Citations (2)

Using radio astronomical receivers for molecular spectroscopic characterization in astrochemical laboratory simulations: A proof of concept

Astronomy and Astrophysics (2017)

Isabel Tanarro Belén Alemán P. de Vicente J. D. Gallego J. R. Pardo

We present a proof of concept on the coupling of radio astronomical receivers and spectrometers with chemical reactors and the performances of the resulting setup for spectroscopy and chemical simulations in laboratory astrophysics. Several experiments including cold plasma generation and UV photochemistry were performed in a 40 cm long gas cell placed in the beam path of the Aries 40 m radio telescope receivers operating in the 41-49 GHz frequency range interfaced with fast Fourier transform spectrometers providing 2 GHz bandwidth and 38 kHz resolution. The impedance matching of the cell windows has been studied using different materials. The choice of the material and its thickness was critical to obtain a sensitivity identical to that of standard radio astronomical observations. Spectroscopic signals arising from very low partial pressures of CH3OH, CH3CH2OH, HCOOH, OCS, CS, SO2 (<10-3 mbar) were detected in a few seconds. Fast data acquisition was achieved allowing for kinetic measurements in fragmentation experiments using electron impact or UV irradiation. Time evolution of chemical reactions involving OCS, O2 and CS2 was also observed demonstrating that reactive species, such as CS, can be maintained with high abundance in the gas phase during these experiments.

Radio Astronomy

Proof of concept

10.1051/0004-6361/201730969

Cite

Citations (14)

Optimization of a Conical Corrugated Antenna Using Multiobjective Heuristics for Radio-Astronomy Applications

International Journal of Antennas and Propagation (2016)

S. López-Ruiz Rocío Sánchez Montero F. Tercero Pablo Luis López Espí J. A. López-Fernández

This paper presents the design of a tree sections corrugated horn antenna with a modified linear profile, using NURBS, suitable for radio-astronomy applications. The operating band ranges from 4.5 to 8.8 GHz. The aperture efficiency is higher than 84% and the return losses are greater than 20 dB in the whole bandwidth. The antenna optimization has been carried out with multiobjective versions of an evolutionary algorithm (EA) and a particle swarm optimization (PSO) algorithm. We show that both techniques provide good antenna design, but the experience carried out shows that the results of the evolutionary algorithm outperform the particle swarm results.

Radio Astronomy

Heuristics

Return loss

Directivity

10.1155/2016/7024704

Cite

Citations (4)

Dyson conical Quad-Spiral Array for VLBI2010

2022 16th European Conference on Antennas and Propagation (EuCAP) (2014)

Alejandro Rivera-Lavado Sergio Llorente‐Romano Francisco Javier Herráiz-Martínez Luis Enrique García-Muñoz Jose-Antonio Lopez-Fernandez

A new topology that potentially can open new solutions for covering the new VLBI2010 configuration and its frequency bands associated is presented in this manuscript. In this approach a single band from 2 to 14 GHz is considered. A log-spiral antenna is printed on a conic surface. The whole structure is adjusted in order to obtain a pure circular polarization at broadside direction. An array of four elements is proposed for obtaining a dual-polarization feeder.

Conic section

Broadside

Multi-band device

Spiral antenna

10.1109/eucap.2014.6901700

Cite

Citations (4)

Focalization of new 40 m radiotelescope of Centro Astronomico de Yebes

Luis Enrique García-Muñoz Leandro de Haro Ariet F. Tercero J. A. López Fernández Belén Galocha Iragüen

The paper presents the solution for the focalization of the new 40 m radiotelescope of the Centro Astronomico de Yebes (CAY) in Guadalajara, Spain. Quasi-optics theory is used for the propagation analysis of the beams through the different optical elements. The goal of the paper is to design the optical system that can focalize several bands reducing to the minimum number of possible optical elements, and sharing the maximum number of them. Hyperbolic lens and ellipsoidal mirror parameters, focal distances, and the feeder dimensions necessary for the focalization in each band are calculated.

Focalization

Ellipsoid

10.1109/aps.2003.1217415

Cite

Citations (0)