281. Wavelength-resolved reverberation mapping of quasar CTS C30.10: Dissecting Mg II and Fe II emission regionsRaj Prince, Michal Zajaček, Bożena Czerny, Piotr Trzcionkowski, Mateusz Bronikowski, Catalina Sobrino Figaredo, Swayamtrupta Panda, Mary Loli Martinez-Aldama, Krzysztof Hryniewicz, Vikram Kumar Jaiswal, Marzena Śniegowska, Mohammad-Hassan Naddaf, Maciej Bilicki, Martin Haas, Marek Jacek Sarna, Vladimir Karas, Aleksandra Olejak, Robert Przyłuski, Mateusz Rałowski, Andrzej Udalski, Ramotholo R. Sefako, Anja Genade, Hannah L. Worters, 2022, original scientific article Abstract: Context. We present the results of the reverberation monitoring of the Mg II broad line and Fe II pseudocontinuum for the luminous quasar CTS C30.10 (z = 0.90052) with the Southern African Large Telescope in 2012–2021.
Aims. We aimed at disentangling the Mg II and UV Fe II variability and the first measurement of UV Fe II time delay for a distant quasar.
Methods. We used several methods for the time-delay measurements and determined the Fe II and Mg II time delays. We also performed a wavelength-resolved time delay study for a combination of Mg II and Fe II in the 2700–2900 Å rest-frame wavelength range.
Results. We obtain a time delay for Mg II of 275.5−19.5+12.4 days in the rest frame, and we have two possible solutions of 270.0−25.3+13.8 days and 180.3−30.0+26.6 in the rest frame for Fe II. Combining this result with the old measurement of Fe II UV time delay for NGC 5548, we discuss for first time the radius-luminosity relation for UV Fe II with the slope consistent with 0.5 within the uncertainties.
Conclusions. Because the Fe II time delay has a shorter time-delay component but the lines are narrower than Mg II, we propose that the line-delay measurement is biased toward the part of the broad line region (BLR) facing the observer. The bulk of the Fe II emission may arise from the more distant BLR region, however, the region that is shielded from the observer.
Keywords: accretion, accretion disks / quasars: emission lines / quasars: individual: CTS C30.10 / techniques: spectroscopic / techniques: photometric
Published in RUNG: 13.11.2023; Views: 616; Downloads: 3
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282. Wavelength-resolved reverberation mapping of intermediate-redshift quasars HE 0413-4031 and HE 0435-4312 : dissecting Mg II, optical Fe II, and UV Fe II emission regionsRaj Prince, Michal Zajaček, Swayamtrupta Panda, Krzysztof Hryniewicz, Vikram Kumar Jaiswal, Bożena Czerny, Piotr Trzcionkowski, Mateusz Bronikowski, Mateusz Rałowski, Catalina Sobrino Figaredo, 2023, original scientific article Abstract: Context. We present the wavelength-resolved reverberation mapping (RM) of combined Mg II and UV Fe II broad-line emissions for two intermediate-redshift (z ∼ 1), luminous quasars, HE 0413-4031 and HE 0435-4312, monitored by the Southern African Large Telescope (SALT) and 1m class telescopes between 2012 and 2022.
Aims. Using a wavelength-resolved technique, we aim to disentangle the Mg II and Fe II emission regions and to build a radius–luminosity (R–L) relation for UV Fe II emission, which has so far remained unconstrained.
Methods. We applied several time-delay methodologies to constrain the time delays for total Mg II and Fe II emissions. In addition, wavelength-resolved RM is performed to quantify the inflow or outflow of broad-line region (BLR) gas around the supermassive black hole and to disentangle the emission and the emitting regions based on lines produced in proximity to each other.
Results. The mean total FeII time delay is nearly equal to the mean total MgII time delay for HE 0435-4312, suggesting the co-spatiality of their emission regions. However, in HE 0413-4031, the mean FeII time delay is found to be longer than the mean MgII time delay, suggesting that FeII emission is produced at greater distances from the black hole. The UV FeII R–L relation is updated with these two quasars (now four in total) and compared with the optical FeII relation (20 sources), which suggests that the optical FeII emission region is located further than the UV FeII region by a factor of 1.7–1.9, that is, RFeII-opt ∼ (1.7 − 1.9)RFeII-UV.
Conclusion. Wavelength-resolved reverberation is an efficient way to constrain the geometry and structure of the BLR. We detected a weak pattern in the time delay versus wavelength relation, suggesting that the MgII broad line originates from a region slightly closer to the SMBH than the UV FeII pseudo continuum, although the difference is not very significant. Comparison of MgII, UV, and optical FeII R–L relations suggests that the difference may be greater for lower-luminosity sources, possibly with the MgII emission originating further from the SMBH. In the future, more RM data will be acquired, allowing better constraints on these trends, in particular the UV FeII R–L relation.
Keywords: accretion, accretion disks, emission lines, photometric, spectroscopic
Published in RUNG: 13.11.2023; Views: 657; Downloads: 4
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284. Sustained delivery of Cu(II)-based DNA intercalators by nanometer-sized cyclodextrin-based porous polymersTina Škorjanc, Julian Heinrich, Damjan Makuc, Nora Kulak, Matjaž Valant, 2023, original scientific article Abstract: DNA intercalators are small molecules that insert between adjacent DNA base pairs and thus disturb DNA replication and transcription, which can lead to cell death. Certain metal complexes are excellent DNA intercalators, and have shown promise in chemotherapy. Here, a cyclodextrin porous polymer was prepared, characterized, exfoliated to form nanometer-sized particles, and used as a delivery vehicle for metal-free and Cu(II)-metalated anthraquinone-based DNA intercalators with a goal to minimize side effects of the highly toxic DNA intercalators. NMR experiments, including DOSY NMR, have shown the interaction between the cyclodextrin building block and the studied DNA intercalators. Porous nature of the delivery vehicle provided ample surface area for interaction with the drug candidates, resulting in encapsulation rates of up to 56%. Sustained cargo release from the polymer was achieved over eight days, and time-dependent cytotoxicity was observed. Furthermore, optical microscopy images indicated delivery vehicle internalization as well as disturbed cellular morphology within 24 hours of incubation. We anticipate that this study will stimulate further interest in the development of polymeric delivery systems for metal complexes.
Keywords: porous organic polymers, cyclodextrin, DNA intercalators, Cu(II) complexes, metal complexes
Published in RUNG: 10.11.2023; Views: 615; Downloads: 4
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286. Crystallizing covalent organic frameworks from metal organic framework through chemical induced-phase engineeringAbdul Khayum Mohammed, Safa Gaber, Jesus Raya, Tina Škorjanc, Nada Elmerhi, Sasi Stephen, Pilar Pena-Sánchez, Felipe Gándara, Steven Hinder, Mark A. Baker, Kyriaki Polychronopoulou, Dinesh Shetty, 2023, original scientific article Abstract: The ordered porous frameworks like MOFs and COFs are generally constructed using the monomers through distinctive metal-coordinated and covalent linkages. Meanwhile, the inter-structural transition between each class of these porous materials is an under-explored research area. However, such altered frameworks are expected to have exciting features compared to their pristine versions. Herein, we have demonstrated a chemical-induction phase-engineering strategy to transform a two dimensional conjugated Cu-based SA-MOF (Cu-Tp) into 2D-COFs (Cu-TpCOFs). The structural phase transition offered in-situ pore size engineering from 1.1 nm to 1.5–2.0 nm. Moreover, the Cu-TpCOFs showed uniform and low percentage-doped (~ 1–1.5%) metal distribution and improved crystallinity, porosity, and stability compared to the parent Cu-Tp MOF. The construction of a framework from another framework with new linkages opens interesting opportunities for phase-engineering.
Keywords: metal organic framework, covalent organic framework, phase engineering, chemical transformation, porous materials
Published in RUNG: 10.11.2023; Views: 698; Downloads: 5
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