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| Pubblicazioni... |
| di Antonio Vagnozzi |
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March 2024 OPEN EUROPEAN JOURNAL ON VARIABLE STARS DOI: 10.5817/OEJV2024-0249 ISSN 1801–5964 LONG TERM OPTICAL VARIABILITY OF TWO HMXB Roberto Nesci,1; Mariateresa Fiocchi,1; Antonio Vagnozzi,2 1) INAF/IAPS, via Fosso del Cavaliere 100, 00133, Roma, Italy 2) MPC589, Via S.Lucia n.68, I-05039, Stroncone (TR), Italy Abstract: We discuss the optical light curves of two Be X-ray Binaries, IGR J06074+2205 and SAX J2103.5+4545, recovered from the ATLAS, ZTF and ASAS-SN databases. Both sources show long term optical variability of 620 and 420 days, respectively, with color redder when brighter. We suggest that this is due to the precession of the circumstellar disk. Another possibility is the propagation of a density wave in the disk. Only these two sources show a large amplitude, periodic optical variability from a sample of 16 well-studied high-mass X-ray Binaries (HMXB) with a Main Sequence primary star.
Optical follow-up of B2 1015+35B ATel #16814; Roberto Nesci (INAF/IAPS), Antonio Vagnozzi (MPC589) on 14 Sep 2024; 06:59 UT Credential Certification: Roberto Nesci (roberto.nesci@inaf.it) Subjects: Optical, Gamma Ray, AGN, Gamma-Ray Burst,Quasar After the announcement of a strong Gamma-ray flare of the Flat Spectrum Radio Quasar B2 1015+35B in ATel #16812 we observed the source with the 30cm telescope of the Santa Lucia di Stroncone Observatory (MPC 589) on 2024-09-14 (MJD 60567) with the R and I (Cousins) filters, respectively for 3000 s and 480 s. Nearby comparison stars were taken from the PanStarrs DR1 catalog (VIZIER II/349, Chambers+ 2016) adopting their rmag and imag magnitudes. Several satellite tracks are present in our images, but luckily they do not cross the Quasar. B2 1015+35B was detected at rmag=17.15 +/-0.07, imag=16.89 +/-0.11. The PanStarrs catalog values are rmag=17.72, imag=17.85, likely not simultaneous. The light curve of the source, available since October 2015 from the ATLAS forced photometry service, shows a slow monotonic luminosity increase with some flares of about half magnitude and about one month long, but stops on June 2024 due to the solar conjunction. A linear extrapolation of the trend to the present date gives rmag=17.28, which is not very different from the observed value. The Quasar reached rmag=16.8 on previous flares (MJD 59304, 59667, 60073), when no Gamma-ray flares were detected by Fermi-LAT according to ATel #16812: the observed present value suggests therefore that there is no correlation between the optical and the Gamma-ray luminosity of the source, at variance with most BL Lac objects. Atel 16814
Optical follow-up of 4U2238+60 (alias SAXJ2239.3+6116) ATel #16803; Roberto Nesci (INAF/IAPS), Mariateresa Fiocchi (INAF/IAPS), Antonio Vagnozzi (MPC589) on 6 Sep 2024; 07:53 UT Credential Certification: Roberto Nesci (roberto.nesci@inaf.it) Subjects: Optical, X-ray, Binary, Neutron Star, Transient, Pulsar Following the ATels #16800 #16762 and #16750 regarding the detection of an X-ray outburst of the HMXB 4U2238+60, we obtained a spectrum of the source with the 50 cm telescope of the S.Lucia di Stroncone Observatory (MPC589) on 2024-09-05. A strong (11 Angstrom equivalent width) was clearly present, as expected if the X-ray emission is due to the interaction of the neutron star with the circumstellar envelope of the Be companion. We point out that past spectroscopic monitoring of the source by Reig et al. (2016, A&A 590, 122) showed a long monotonic decrease of the line from 2001 (E.W. 12 Angstrom) to 2015 (E.W. 2 Angstrom). Archival (unpublished) spectra of the Stroncone Observatory taken in July and August 2022 show that the H-alpha line was again strong (11 Angstrom E.W.). Given the orbital period of 262 days (in't Zand 2000, A&A 361, 85) X-ray outbursts should have happened around 2022-06-08, 2023-02-25 and 2023-11-14 . Atel 16803
CBAT "Transient Object Followup Reports" PNV J00215475+5231007 Andreoli.V ; Vagnozzi.A We obtained two low resolution spectra of PNV J00215475+5231007, on 2023-01-10.799 and 2023-01.10.844, the first with 0.25-m telescope + alpy600 spectrograph (resolution 4.96 Ang/pix) located in Novezzina (Italy) and the second with a 0.5 m telescope + MARK III spectrograph self-built with resolution 3.2 Ang/pix) located in Stroncone (Italy). Both spectrums show a blue continuum and absorption of Balmer lines, typical of Cataclysmic Variable (CV) outburst. We propose the classification as a Cataclysmic Variable.
A new outburst of the symbiotic star V919 Sgr, again 15 yrs past the previous one ATel #15528; U. Munari (INAF Padova), A. Vagnozzi, A. Maitan, F. Castellani, M. Graziani (ANS Collaboration), P. Ochner, A. Reguitti (Padova Univ.) on 25 Jul 2022; 15:44 UT Credential Certification: U. Munari (ulisse.munari@oapd.inaf.it) Subjects: Optical, Cataclysmic Variable Referred to by ATel #: 15542 Atel 15528
Photometry and spectroscopy of Nova Cas 2020 (TCP J00114297+6611190) ATel #13905; U. Munari (INAF Padova), A. Siviero (Univ. Padova), A. Vagnozzi (ANSCollaboration),br> K. Sokolovsky and E. Aydi (MSU)on 30 Jul 2020; 09:01 UT Credential Certification: U. Munari (ulisse.munari@oapd.inaf.it) Atel 13905(PDF) (PDF)
Photometry and spectroscopy of the FeII nova AT 2020lrv still rising in brightness ATel #13807; U. Munari (INAF Padova), P. Ochner (Univ. Padova), A. Vagnozzi, S. Moretti, P. Valisa, A. Maitan, and S. Dallaporta (ANS Collaboration) on 15 Jun 2020; 08:51 UT Credential Certification: U. Munari (ulisse.munari@oapd.inaf.it) Atel 13807(PDF) (PDF)
The optical counterpart of the X-ray source 2SXPS J173508.4-292958 is a new, yellow-type symbiotic star. U. Munari (INAF Padova), P. Valisa, S. Dallaporta, A. Vagnozzi, V. Andreoli, F. Castellani (ANS Collaboration) With an assortment of telescopes operated by ANS Collaboration, we have obtained optical spectroscopy (low and high resolution) and BVRI photometry of the optical counterpart of 2SXPS J173508.4-292958, the source recently reported by Heinke et al.(ATel 13648) to have brightened in the X-rays. (Atel 13660) (PDF) Nova ASASSN-17hx fast returning to maximum brightness, now at much larger velocities U. Munari (INAF Padova), P. Ochner (Univ. Padova), F.-J. Hambsch, A. Frigo, F. Castellani, A. Milani, P. Valisa, A. Vagnozzi (ANS Collaboration) on 11 Sep 2017; 21:54 UT Credential Certification: U. Munari (ulisse.munari@oapd.inaf.it) (ATel_10736) Congratulations! Your paper is one of the 5 most highly cited papers published in New Astronomy. Dear Dr. Munari, The editors of New Astronomy are delighted to inform you that your paper, BVRI lightcurves of supernovae SN 2011fe in M101, SN 2012aw in M95, and SN 2012cg in NGC 4424, published in 2013 is one of the most highly cited papers during 2014, 2015 and up until June 2016. We would like to take this opportunity to thank you for publishing with us and to congratulate you (PDF) (PDF) The symbiotic star TX CVn has entered an active state. U. Munari, F. Castellani, P. Valisa, S. Dallaporta, G. Cherini, A. Vagnozzi, G. L. Righetti, R. Belligoli 14 Jan 2014; 15:56 UT ATel 5761 (2014) (PDF) BVRI lightcurves of supernovae SN 2011fe in M101, SN 2012aw in M95, and SN 2012cg in NGC 4424 U. Munari, A. Henden, R. Belligoli, F. Castellani, G. Cherini, G.L. Righetti, A. Vagnozzi (PDF) (light curve) The 82nd Name-List of Variable Stars Part I - RA 0hr to 18hr, Novae and Globular-cluster Variables Kazarovets, E. V.; Samus, N. N.; Durlevich, O. V.; Khruslov, A. V.; Kireeva, N. N.; Pastukhova, E. N. Abstract We present the first part of a new Name-List of variable stars containing information on 1291 variable stars recently designated in the system of the General Catalogue of Variable Stars. With the exception of Novae and other unusual variables named upon request from the IAU CBAT or by our initiative, these stars are in the range of J2000.0 right ascensions from 0 hours to 18 hours 00 minutes. The paper also announces GCVS designations for 324 known variables in 10 globular clusters. Publication: Information Bulletin on Variable Stars, No. 6261, #1. Pub Date: February 2019 DOI: 10.22444/IBVS.6261 Bibcode: 2019IBVS.6261....1K Keywords: variable stars; catalogues The ANS Collaboration Monitoring Program Munari, U., Bacci, S., Baldinelli, L., Castellani, F., Cetrulo, G., Cherini, G., Dallaporta, S., Dallavia, G., Englaro, A., Frigo, A., Graziani, M., Luppi, V., Maitan, A., Marangoni, C., Milani, A., Moretti, S., Moschini, F., Ochner, P., Siviero, A., Righetti, G. L., Tomaselli, S., Tomasoni, S., Vagnozzi, A., Valisa, P. Informational Bulletin on Variable Stars Baltic Astronomy, vol.21, 2012 (PDF) SUPERNOVA 2012aw IN M95 = PSN J10435372+1140177 A. Vagnozzi, F. Castellani 2012 CBET 3054 (PDF) Formation of a disk structure in the symbiotic binary AX Per during its 2007-10 precursor-type activity A. Skopal, T. N. Tarasova, Z. Cariková, F. Castellani, G. Cherini, S. Dallaporta, A. Frigo, C. Marangoni, S. Moretti, U. Munari, G. L. Righetti, A. Siviero, S. Tomaselli, A. Vagnozzi, P. Valisa (PDF) AX PERSEI Munari, U., Siviero, A., Dallaporta, S., Cherini, G., Valisa, P., Castellani, F., Frigo, A., Vagnozzi, A., Bacci, S., Righetti, G., Moretti, S., Tomaselli, S. 2009, CBET, 1757 (PDF) |
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