We report the lens mass and distance measurements of the nearby microlensing event TCP J05074264+2447555 (Kojima-1). We measure the microlens parallax vector using Spitzer and ground-based light ...curves with constraints on the direction of lens-source relative proper motion derived from Very Large Telescope Interferometer (VLTI) GRAVITY observations. Combining this determination with the angular Einstein radius measured by VLTI-GRAVITY observations, we find that the lens is a star with mass at a distance DL = 429 21 pc. We find that the blended light basically all comes from the lens. The lens-source proper motion is , so with currently available adaptive-optics instruments, the lens and source can be resolved in 2021. This is the first microlensing event whose lens mass is unambiguously measured by interferometry + satellite-parallax observations, which opens a new window for mass measurements of isolated objects such as stellar-mass black holes.
ABSTRACT
We present an extensive recent multiband optical photometric observations of the blazar S5 0716+714 carried out over 53 nights with two telescopes in India, two in Bulgaria, one in Serbia, ...and one in Egypt during 2019 November – 2022 December. We collected 1401, 689, 14726, and 165 photometric image frames in B, V, R, and I bands, respectively. We monitored the blazar quasi-simultaneously during three nights in B, V, R, and I bands; four nights in B, V, and R; two nights in V, R, and I; five nights in B and R; and two nights in V and R bands. We also took 37 nights of data only in R band. Single band data are used to study intraday flux variability and two or more bands quasi-simultaneous observations allow us to search for colour variation in the source. We employ the power-enhanced F-test and the nested ANOVA test to search for genuine flux and colour variations in the light curves of the blazar on intraday time-scales. Out of 12, 11, 53, and 5 nights observations, intraday variations with amplitudes between ∼3 and ∼20 per cent are detected in 9, 8, 31 and 3 nights in B, V, R, and I bands, respectively, corresponding to duty cycles of 75, 73, 58, and 60 per cent. These duty cycles are lower than those typically measured at earlier times. On these time-scales colour variations with both bluer-when-brighter and redder-when-brighter are seen, though nights with no measurable colour variation are also present. We briefly discuss possible explanations for this observed intraday variability.
ABSTRACT
Based on the Gaia EDR3 astrometric parameters and our new systemic radial velocity of the high-mass X-ray binary 4U 2206+54/BD+532790, we studied the trace back motion of the system and ...propose that it originated in the subgroup of the Cepheus OB1 association (Age ∼4–10 Myr) with its brightest star, BD+532820 (B0V; ${\cal L}$∼104.7${\cal L}$⊙). The kinematic age of 4U 2206+54 is about 2.8 ± 0.4 Myr, it is at a distance of 3.1–3.3 kpc and has a space velocity of 75–100 km s−1 with respect to this member star (BD+532820) of the Cep OB1 association. This runaway velocity indicates that the progenitor of the neutron star hosted by 4U 2206+54 lost about 4–9 M⊙ during the supernova explosion and the latter one received a kick velocity of at least 200–350 km s−1 . Since the high-mass X-ray binary 4U 2206+54/BD+532790 was born as a member of a subgroup of Cep OB1, the initially most massive star in the system terminated its evolution within $\lesssim 7-9$ Myr, corresponding to an initial mass $\gtrsim 32$ M⊙.
Context. M31N 2015-01a (or M31LRN 2015) is a red nova that erupted in January 2015 – the first event of this kind observed in M 31 since 1988. Very few similar events have been confirmed as of 2015. ...Most of them are considered to be products of stellar mergers. Aims. Results of an extensive optical monitoring of the transient in the period January–March 2015 are presented. Methods. Eight optical telescopes were used for imaging. Spectra were obtained on the Large Altazimuth Telescope (BTA), the Gran Telecsopio Canarias (GTC) and the Rozhen 2 m telescope. Results. We present a highly accurate 70 d light curve and astrometry with a 0.05′′uncertainty. The colour indices reached a minimum of 2−3 d before peak brightness and rapidly increased afterwards. The spectral type changed from F5I to F0I in 6 d before the maximum and then to K3I in the next 30 d. The luminosity of the transient was estimated to be 8.7+3.3-2.2 × 105 L⊙ during the optical maximum. Conclusions. Both the photometric and the spectroscopic results confirm that the object is a red nova, similar to V838 Monocerotis.
A multifrequency campaign on the BL Lac object PG 1553+113 was organized by the Whole Earth Blazar Telescope (WEBT) in 2013 April–August, involving 19 optical, two near-IR, and three radio ...telescopes. The aim was to study the source behaviour at low energies during and around the high-energy observations by the Major Atmospheric Gamma-ray Imaging Cherenkov telescopes in April–July. We also analyse the UV and X-ray data acquired by the Swift and XMM–Newton satellites in the same period. The WEBT and satellite observations allow us to detail the synchrotron emission bump in the source spectral energy distribution (SED). In the optical, we found a general bluer-when-brighter trend. The X-ray spectrum remained stable during 2013, but a comparison with previous observations suggests that it becomes harder when the X-ray flux increases. The long XMM–Newton exposure reveals a curved X-ray spectrum. In the SED, the XMM–Newton data show a hard near-UV spectrum, while Swift data display a softer shape that is confirmed by previous Hubble Space Telescope/Cosmic Origins Spectrograph and International Ultraviolet Explorer observations. Polynomial fits to the optical–X-ray SED show that the synchrotron peak likely lies in the 4–30 eV energy range, with a general shift towards higher frequencies for increasing X-ray brightness. However, the UV and X-ray spectra do not connect smoothly. Possible interpretations include: (i) orientation effects, (ii) additional absorption, (iii) multiple emission components, and (iv) a peculiar energy distribution of relativistic electrons. We discuss the first possibility in terms of an inhomogeneous helical jet model.
We analyzed the optical photometric data of short‐term variability (flickering) of the accreting white dwarf in the jet‐ejecting symbiotic star MWC 560. The observations were obtained on 17 nights ...during the period November 2011 to October 2019. The color‐magnitude diagram shows that the hot component of the system becomes redder as it gets brighter. For the flickering source, we find that it has color 0.14 < B − V < 0.40, temperature in the range 6,300 < Tfl < 11,000 K, and radius 1.2 < Rfl < 18 R⊙. We find a strong correlation (correlation coefficient 0.76, significance <0.001) between B band magnitude and the average radius of the flickering source—as the brightness of the system increases, the size of the flickering source also increases. The estimated temperature is similar to that of the bright spot of cataclysmic variables. In 2019, the flickering was missing, and the B–V color of the hot component became bluer.
AIM： To study the influence of tumor removal on the serum level of IgG antibodies to tumor-associated Thomsen-Friedenreich （TF）, Tn carbohydrate epitopes and xenogeneic αGal, and to elucidate on the ...change of the level during the follow-up as well as its association with the stage and morphology of the tumor and the values of blood parameters in gastrointestinal cancer. METHODS： Sixty patients with gastric cancer and 34 patients with colorectal cancer in stages Ⅰ-Ⅳ without distant metastases were subjected to follow- up. The level of antibodies in serum was determined by the enzyme-linked immunosorbent assay （ELISA） using synthetic polyacrylamide （PAA） glycoconjugates. Biochemical and haematological analyses were performed using automated equipment. RESULTS： In gastrointestinal cancer, the TF antibody level was found to have elevated significantly after the removal of G3 tumors as compared with the preoperative level （u = 278.5, P 〈 0.05）. After surgery, the TF and Tn antibody level was elevated in the majority of gastric cancer patients （sign test, 20 vs 8, P 〈 0.05, and 21 vs 8, P 〈 0.05, respectively）. In gastrointestinal cancer, the elevated postoperative level of TF, Tn and αGal antibodies was noted in most patients with G3 tumors （sign test, 22 vs 5, P 〈 0.01; 19 vs 6, P 〈 0.05; 24 vs 8, P 〈 0.01, respectively）, but the elevation was not significant in patients with G1 ＋ G2 resected tumors. The postoperative follow-up showed that the percentage of patients with G3 resected tumors of the digestive tract, who had a mean level of anti-TF IgG above the cut- off value （1.53）, was significantly higher than that of patients with G1 ＋ G2 resected tumors （χ2 = 3.89, all patients; χ2 = 5.34, patients without regional lymph node metastases; P 〈 0.05）. The percentage of patients with a tumor in stage I, whose mean anti-TF IgG level remained above the cut-off value （1.26）, was significantly higher than that of patients with the cancer in stages Ⅲ-Ⅳ （χ2 = 4.71, gastric cancer; χ2 = 4.11, gastrointestinal cancer; P 〈 0.05）. The correlation was observed to exist between the level of anti-TF IgG and the count of lymphocytes （r = 0.517, P 〈 0.01）, as well as between the level of anti- Tn IgG and that of serum CA 19-9 （r = 0.481, P 〈 0.05）. No positive delayed-type hypersensitivity reaction in skin test challenges with TF-PAA in any of the fifteen patients, including those with a high level of anti-TF IgG, was observed. CONCLUSION： The surgical operation raises the level of anti-carbohydrate IgG in most patients, especially in those with the G3 tumor of the gastrointestinal tract. The follow-up demonstrates that after surgery the low preoperative level of TF antibodies may be considerably increased in patients with the carcinoma in its early stage but remains low in its terminal stages. The stage- and morphology-dependent immunosuppression affects the TF-antibody response and may be one of the reasons for unresponsiveness to the immunization with TF-antigens.
Blazars are active galactic nuclei (AGN) with relativistic jets whose non-thermal radiation is extremely variable on various timescales
. This variability seems mostly random, although some ...quasi-periodic oscillations (QPOs), implying systematic processes, have been reported in blazars and other AGN. QPOs with timescales of days or hours are especially rare
in AGN and their nature is highly debated, explained by emitting plasma moving helically inside the jet
, plasma instabilities
or orbital motion in an accretion disc
. Here we report results of intense optical and γ-ray flux monitoring of BL Lacertae (BL Lac) during a dramatic outburst in 2020 (ref.
). BL Lac, the prototype of a subclass of blazars
, is powered by a 1.7 × 10
M
(ref.
) black hole in an elliptical galaxy (distance = 313 megaparsecs (ref.
)). Our observations show QPOs of optical flux and linear polarization, and γ-ray flux, with cycles as short as approximately 13 h during the highest state of the outburst. The QPO properties match the expectations of current-driven kink instabilities
near a recollimation shock about 5 parsecs (pc) from the black hole in the wake of an apparent superluminal feature moving down the jet. Such a kink is apparent in a microwave Very Long Baseline Array (VLBA) image.
The elevated anti-GalNAcβ IgG level of serum was shown to be associated with the significantly better survival of patients with gastrointestinal cancer.
To characterize the specificity of IgG ...antibodies to GalNAcβ-terminated glycans of long-term gastric cancer survivors.
Serum antibodies and affinity-isolated antibodies were analysed by the indirect and competitive ELISA using glycan-polyacrylamide (PAA) conjugates as well as by isoelectric focusing and Western blotting.
In the serum probes, a partial cross-reactivity of antibodies to GalNAcβ, GalNAcβ1-3Galβ (X2di), GalNAcβ1-3GalNAcβ (PFdi) and GlcNAcβ was observed. The isolated anti-GalNAcβ IgGs demonstrated the cross-reactivity to the X2di glycan mainly. The affinity of the X2di-PAA to anti-GalNAcβ IgGs was 11-21 times lower than that of the GalNAcβ-PAA. Anti-X2di and anti-PFdi IgGs demonstrated monoreactivity to their key glycans-PAA used in isolation. The IC50 values of key glycoconjugates ranged from 1 to 5 · 10(-7) M. No polyreactivity of antibodies to the unrelated antigens (ferritin, casein and DNA) was found. The polyclonal or oligoclonal distribution of IgG bands was established and the monoreactivity of antibodies was not associated with the clonal distribution of bands.
The cross-reactivity of anti-GalNAcβ antibodies to X2di and related glycans deserves attention in the clarification of the role of antibodies in cancer progression and enhancement of the prognostic potential in the combined determination of antibody markers.
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