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A natureza dos braços espirais nucleares na galáxia ativa Arp 102B

Couto, Guilherme dos Santos
Fonte: Universidade Federal do Rio Grande do Sul Publicador: Universidade Federal do Rio Grande do Sul
Tipo: Dissertação Formato: application/pdf
POR
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Neste trabalho estudamos a região central da galáxia LINER/Seyfert 1 Arp 102B na tentativa de descobrir a natureza dos recentemente descobertos braços espirais nucleares. Apresentamos uma análise bi-dimensional da excitação e cinemática do gás nos 2.5 kpc X 1.7 kpc internos, a partir de espectros ópticos obtidos com o espectrógrafo de campo integral do instrumento GMOS no telescópio Gemini Norte, com resolução espacial de ≈ 250 pc. Nossos mapas de fluxo nas linhas de emissão mostram os mesmos braços espirais nucleares descobertos em imagens feitas com o Telescópio Espacial Hubble. Um jato rádio, observado em 8.4 GHz com o VLA, está correlacionado com o braço espiral a leste. Outro braço é observado a oeste. Valores de razões de linhas típicos de núcleos ativos excluem ionização do gás por estrelas, restando choques e radiação diluída como possíveis fontes de ionização. Uma região de alta densidade do gás _e observada na borda ao norte do braço leste, numa região onde o jato rádio parece ser deexionado. Mapas de velocidade centroide mostram um padrão de rotação distorcido, com blueshifts a leste e redshifts a oeste. Channel maps mostram blueshifts e redshifts no local do jato rádio (e braço a leste)...

The Arabidopsis thaliana apurinic endonuclease Arp reduces human transcription factors Fos and Jun.

Babiychuk, E; Kushnir, S; Van Montagu, M; Inzé, D
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em 12/04/1994 EN
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An Arabidopsis thaliana cDNA encoding an analogue, referred to as Arp for apurinic endonuclease-redox protein, of the human redox factor REF has been cloned. Arp stimulates in vitro DNA-binding activity of the human transcription factor Jun and Fos by the reduction of a cysteine residue located in the DNA-binding domain. Based on amino acid sequence homology, this redox activity is probably confined to the small internal domain of the Arp protein. In analogy to REF, we show that the Arabidopsis Arp protein also functions as an apurinic/apyrimidinic class II endonuclease. This base-free endonuclease activity resides in the carboxyl-terminal domain, and this part of the protein has significant sequence similarity to bacterial (Escherichia coli exonuclease III and Streptococcus pneumoniae exonuclease A) and animal (Drosophila Rrp1 and human REF/HAP) apurinic/apyrimidinic endonucleases. The amino-terminal domain of the Arp protein is highly charged and apparently increases the affinity of the protein for DNA. Therefore, the Arabidopsis Arp protein is multifunctional and may be involved both in DNA repair and in the regulation of transcription.

A dynamic balance between ARP-1/COUP-TFII, EAR-3/COUP-TFI, and retinoic acid receptor:retinoid X receptor heterodimers regulates Oct-3/4 expression in embryonal carcinoma cells.

Ben-Shushan, E; Sharir, H; Pikarsky, E; Bergman, Y
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /02/1995 EN
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The Oct-3/4 transcription factor is a member of the POU family of transcription factors and, as such, probably plays a crucial role in mammalian embryogenesis and differentiation. It is expressed in the earliest stages of embryogenesis and repressed in subsequent stages. Similarly, Oct-3/4 is expressed in embryonal carcinoma (EC) cells and is repressed in retinoic acid (RA)-differentiated EC cells. Previously we have shown that the Oct-3/4 promoter harbors an RA-responsive element, RAREoct, which functions in EC cells as a binding site for positive regulators of transcription and in RA-differentiated EC cells as a binding site for positive regulators of transcription and in RA-differentiated EC cells as a binding site for negative regulators. Our present results demonstrate that in P19 and RA-treated P19 cells, the orphan receptors ARP-1/COUP-TFII and EAR-3/COUP-TFI repress Oct-3/4 promoter activity through the RAREoct site in a dose-dependent manner. While the N-terminal region of the ARP-1/COUP-TFII receptor is dispensable for this repression, the C-terminal domain harbors the silencing region. Interestingly, three different RA receptor:retinoid X receptor (RAR:RXR) heterodimers, RAR alpha:RXR alpha, RAR beta:RXR alpha, and RAR beta:RXR beta...

Functional domains of the human orphan receptor ARP-1/COUP-TFII involved in active repression and transrepression.

Achatz, G; Hölzl, B; Speckmayer, R; Hauser, C; Sandhofer, F; Paulweber, B
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /09/1997 EN
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The orphan receptor ARP-1/COUP-TFII, a member of the chicken ovalbumin upstream promoter transcription factor (COUP-TF) subfamily of nuclear receptors, strongly represses transcriptional activity of numerous genes, including several apolipoprotein-encoding genes. Recently it has been demonstrated that the mechanism by which COUP-TFs reduce transcriptional activity involves active repression and transrepression. To map the domains of ARP-1/COUP-TFII required for repressor activity, a detailed deletion analysis of the protein was performed. Chimeric proteins in which various segments of the ARP-1/COUP-TFII carboxy terminus were fused to the GAL4 DNA binding domain were used to characterize its active repression domain. The smallest segment confering active repressor activity to a heterologous DNA binding domain was found to comprise residues 210 to 414. This domain encompasses the region of ARP-1/COUP-TFII corresponding to helices 3 to 12 in the recently published crystal structure of other members of the nuclear receptor superfamily. It includes the AF-2 AD core domain formed by helix 12 but not the hinge region, which is essential for interaction with a corepressor in the case of the thyroid hormone and retinoic acid receptor. Attachment of the nuclear localization signal from the simian virus 40 large T antigen (Flu tag) to the amino terminus of ARP-1/COUP-TFII abolished its ability to bind to DNA without affecting its repressor activity. By using a series of Flu-tagged mutants...

Transcriptional activation by the orphan nuclear receptor ARP-1.

Malik, S; Karathanasis, S
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em 11/05/1995 EN
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ARP-1 is a ubiquitous orphan nuclear receptor that binds to a site (site A) in the apolipoprotein AI (apoAI) liver-specific enhancer and represses its transcriptional activity in hepatoblastoma HepG2 cells. Electrophoretic mobility shift analysis of HepG2 cell nuclear extracts showed that in addition to ARP-1, site A also binds the orphan nuclear receptors Ear-2 and HNF-4. In in vitro transcription assays, Hela cell nuclear extracts which contain ARP-1 had no effect on transcription from a basal promoter linked to multiple copies of site A. However, supplementation of these extracts with excess amounts of recombinant ARP-1 resulted in significant stimulation. Supplementation of the extracts with purified polypeptides representing fusions between the ARP-1 N- or C-terminal domains and the yeast activator GAL4 DNA binding domain also stimulated transcription from a basal promoter linked to multiple GAL4 DNA binding sites. Co-immunoprecipitation assays using ARP-1-selective antibodies revealed specific physical interactions between ARP-1 and the basal transcription factor TFIIB. We conclude that ARP-1 possesses intrinsic transcription activation potential which is modulated, at least in part, by the intracellular balance of other nuclear receptors that also bind to its cognate DNA binding site.

Repression by ARP-1 sensitizes apolipoprotein AI gene responsiveness to RXR alpha and retinoic acid.

Widom, R L; Rhee, M; Karathanasis, S K
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /08/1992 EN
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The gene coding for apolipoprotein AI (apoAI), a lipid binding protein involved in the transport of cholesterol and other lipids in the plasma, is expressed in mammals predominantly in the liver and the intestine. Liver-specific expression is controlled by synergistic interactions between transcription factors bound to three separate sites, sites A (-214 to -192), B (-169 to -146), and C (-134 to -119), within a powerful liver-specific enhancer located between nucleotides -222 and -110 upstream of the apoAI gene transcription start site (+1). Previous studies in our laboratory have shown that ARP-1, a member of the nuclear receptor superfamily whose ligand is unknown (orphan receptor), binds to site A and represses transcription of the apoAI gene in liver cells. In a more recent series of experiments, we found that site A is a retinoic acid (RA) response element that responds preferentially to the recently identified RA-responsive receptor RXR alpha over the previously characterized RA receptors RAR alpha and RAR beta. In this study we investigated the combined effects of ARP-1 and RXR alpha on apoAI gene expression in liver cells. Transient transfection assays showed that site A is necessary and sufficient for RXR alpha-mediated transactivation of the apoAI gene basal promoter in human hepatoma HepG2 cells in the presence of RA and that this transactivation is abolished by increasing amounts of cotransfected ARP-1. Electrophoretic mobility shift assays and subsequent Scatchard analysis of the data revealed that ARP-1 and RXR alpha bind to site A with similar affinities. These assays also revealed that ARP-1 and RXR alpha bind to site A as heterodimers with an affinity approximately 10 times greater than that of either ARP-1 or RXR alpha alone. Further transfection assays in HepG2 cells...

Expression of the replication protein Arp of phasyl shows dual regulation by an antisense promoter.

Gielow, A; Diederich, L; Messer, W
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /10/1991 EN
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Phasyl is the smallest naturally occurring replicon found so far in Escherichia coli. It encodes a protein which is essential for autonomous replication (Arp). The transcriptional start of the arp gene was mapped. A strong antisense promoter was found in close proximity to the arp promoter. The inactivation of this promoter led in cis to a strong increase of the transcription of the arp gene and to the inactivation of autonomous replication of phasyl. The product of the antisense promoter is an 83 nt RNA molecule, which is not translated. The antisense RNA led in trans to the inhibition of the translation of the arp mRNA, presumably mediated by the formation of an RNA-RNA hybrid in which the Shine-Dalgarno sequence of the arp transcript is sequestered. The expression of the arp gene is thus controlled by two negatively acting mechanisms: it is subject to a transcriptional control in cis exerted by the antisense promoter and to a translational control in trans mediated by the antisense RNA. Inactivation of one mechanism of control cannot be compensated by the remaining one.

ARP, a peptide derived from the stress-associated acetylcholinesterase variant, has hematopoietic growth promoting activities.

Grisaru, D.; Deutsch, V.; Shapira, M.; Pick, M.; Sternfeld, M.; Melamed-Book, N.; Kaufer, D.; Galyam, N.; Gait, M. J.; Owen, D.; Lessing, J. B.; Eldor, A.; Soreq, H.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /02/2001 EN
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BACKGROUND: Psychological stress induces rapid and long-lasting changes in blood cell composition, implying the existence of stress-induced factors that modulate hematopoiesis. Here we report the involvement of the stress-associated "readthrough" acetylcholinesterase (AChE-R) variant, and its 26 amino acid C-terminal domain (ARP) in hematopoietic stress responses. MATERIALS AND METHODS: We studied the effects of stress, cortisol, antisense oligonucleotides to AChE, and synthetic ARP on peripheral blood cell composition and clonogenic progenitor status in mice under normal and stress conditions, and on purified CD34 cells of human origin. We employed in situ hybridization and immunocytochemical staining to monitor gene expression, and 5-bromo-2-deoxyuridine (BrdU), primary liquid cultures, and clonogenic progenitor assays to correlate AChE-R and ARP with proliferation and differentiation of hematopoietic progenitors. RESULTS: We identified two putative glucocorticoid response elements in the human ACHE gene encoding AChE. In human CD34+ hematopoietic progenitor cells, cortisol elevated AChE-R mRNA levels and promoted hematopoietic expansion. In mice, a small peptide crossreacting with anti-ARP antiserum appeared in serum following forced swim stress. Ex vivo...

Presence of Arp Specifically Contributes to Joint Tissue Edema Associated with Early-Onset Lyme Arthritis

Hove, Petronella R.; Haldorson, Gary J.; Magunda, Forgivemore; Bankhead, Troy
Fonte: American Society for Microbiology Publicador: American Society for Microbiology
Tipo: Artigo de Revista Científica
Publicado em /01/2014 EN
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Antiserum to the Borrelia burgdorferi arthritis-related protein, Arp, has been shown to prevent or reduce arthritis in immunodeficient mice. To directly investigate the requirement for this lipoprotein in the generation of Lyme arthritis, we utilized targeted deletion to generate a B. burgdorferi clone that lacked only the arp gene locus. Infection of Lyme disease-susceptible C3H/HeN mice with the arp deletion mutant demonstrated significantly reduced tibiotarsal joint swelling during the first 6 weeks of infection compared to a wild-type control. The severity of joint swelling was restored to wild-type levels in mice infected with an arp mutant clone complemented in cis. Interestingly, the reduced swelling of joint tissues exhibited by mice infected with the arp deletion mutant did not directly correspond to reduced underlying arthritis. Histopathology data at 2 weeks postinfection showed some reduction in arthritis severity caused by the arp mutant clone; however, by 8 weeks, no significant difference was observed between joint tissues infected by the wild-type or arp mutant clones. The spirochete load in the joint tissues of mice infected with the arp mutant was found to be greater than that exhibited by the wild-type control. Our findings demonstrate that this lipoprotein contributes to the generation of early-onset joint swelling and suggests that arp expression has a negative secondary effect on total spirochete numbers in joint tissues.

Caracterização funcional de dois cDNAs homólogos à ciclofilina e à proteína reprimida por auxina (ARP) identificados em bibliotecas subtrativas a para floração em tomateiro

Estevam, Renata Kaline Souza
Fonte: Universidade Federal do Rio Grande do Norte; BR; UFRN; Programa de Pós-Graduação em Bioquímica; Bioquímica; Biologia Molecular Publicador: Universidade Federal do Rio Grande do Norte; BR; UFRN; Programa de Pós-Graduação em Bioquímica; Bioquímica; Biologia Molecular
Tipo: Dissertação Formato: application/pdf
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Flowering is a fundamental process in the life cycle for plant. This process is marked by vegetative to reproductive apical meristem conversion, due to interactions between several factors, both internal and external to plant. Therefore, eight subtractive libraries were constructed using apical meristem induced or not induced for two contrasting species: Solanum lycopersicum cv. Micro-Tom and Solanum pimpinellifolium. Several cDNAs were identified and among these, were selected two cDNAs: one homologous cDNA to cyclophilin (LeCYP1) and the other to Auxin repressed protein (ARP). It has observed that LeCYP1 and ARP genes are important in the developmental process to plants. In silico analysis, were used several databases with the exclusion criterion E-value <1.0x10-15. As a result, conservation was observed for proteins analyzed by means of multiple alignments and the presence of functional domains. Then, overexpression cassettes were constructed for the ARP cDNA in sense and antisense orientations. For this step, it was used the CaMV35S promoter. The cDNA orientation (sense or antisense) in relation to the promoter was determined by restriction enzymes and sequencing. Then, this cassette was transferred to binary vector pZP211 and these cassettes were transferred into Agrobacterium tumefaciens LBA4404. S. lycopersicum cv. Micro-Tom (MT) and MT-Rg1 plants were transformed. In addition...

ARP-Path Bridges: Implementación de Shortest Path Bridges Ethernet basados en ARP sobre Linux y Openflow/NetFPGA

Ibáñez, Guillermo; Naous, Jad; Rojas, Elisa; Rivera, Diego; Carral, Juan A.; Velasco, Juan R.
Fonte: XX Jornadas de Telecom I+D Publicador: XX Jornadas de Telecom I+D
Tipo: info:eu-repo/semantics/conferenceObject; acceptedVersion Formato: application/pdf
SPA
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En este artículo se describen los conmutadores ARP-Path (también denominados FastPath y sus implementaciones recientes en Linux y NetFPGA. ARP-Path es una evolución conceptual de los puentes transparentes con aprendizaje que no requiere protocolo auxiliar de encaminamiento (ni de árbol de expansión) en capa dos, a diferencia de las propuestas actualmente en estandarización RBridges y Shortest Path Bridges. Cada host establece, en los conmutadores ARP-Path, un camino mínimo al mismo tiempo que se envía el paquete estándar ARP_Request, pero inundado por todos los enlaces. El camino marcado por el paquete ARP Request que alcanza el destino se confirma aprovechando el paquete ARP_Reply de respuesta del host destino. Se han realizado implementaciones de puentes ARP-Path en Linux y en la plataforma Openflow con tarjetas NetFPGA (actualmente en pruebas), así como simulaciones sobre Omnet. Las prestaciones son similares o ligeramente superiores a las de enrutadores de camino mínimo y muy superiores a STP. Las pruebas con tráfico real y de reconfiguración muestran las robustez y rapidez del protocolo. ARP-Path no modifica la trama de Ethernet y es compatible con puentes estándar en modo núcleo-isla.

Uncovering the Deeply Embedded Active Galactic Nucleus Activity in the Nuclear Regions of the Interacting Galaxy Arp 299

Alonso Herrero, Almudena; Roche, Patrick F.; Esquej Alonso, María Pilar; González Martín, Omaira; Pereira Santaella, M.; Ramos Almeida, Cristina; Levenson, Nancy A.; Packham, Christopher; Asensio Ramos, A.; Mason, Rachel E.; Rodríguez Espinosa, José
Fonte: American Astronomical Society; Institute of Physics Publicador: American Astronomical Society; Institute of Physics
Tipo: info:eu-repo/semantics/article; publishedVersion
ENG
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We present mid-infrared (MIR) 8-13 μm spectroscopy of the nuclear regions of the interacting galaxy Arp 299 (IC 694+NGC 3690) obtained with CanariCam (CC) on the 10.4 m Gran Telescopio Canarias (GTC). The high angular resolution (~0.'3-0.'6) of the data allows us to probe nuclear physical scales between 60 and 120 pc, which is a factor of 10 improvement over previous MIR spectroscopic observations of this system. The GTC/CC spectroscopy displays evidence of deeply embedded active galactic nucleus (AGN) activity in both nuclei. The GTC/CC nuclear spectrum of NGC 3690/Arp 299-B1 can be explained as emission from AGN-heated dust in a clumpy torus with both a high covering factor and high extinction along the line of sight. The estimated bolometric luminosity of the AGN in NGC 3690 is 3.2 ± 0.6 × 1044 erg s–1. The nuclear GTC/CC spectrum of IC 694/Arp 299-A shows 11.3 μm polycyclic aromatic hydrocarbon emission stemming from a deeply embedded (AV ~ 24 mag) region of less than 120 pc in size. There is also a continuum-emitting dust component. If associated with the putative AGN in IC 694, we estimate that it would be approximately five times less luminous than the AGN in NGC 3690. The presence of dual AGN activity makes Arp 299 a good example to study such phenomena in the early coalescence phase of interacting galaxies.

Molecular gas in Arp 94: implications for intergalactic star formation

Lisenfeld, Ute; Mundell, C.; Allsopp, J.; Schinnerer, Eva
Fonte: Elsevier B.V. Publicador: Elsevier B.V.
Tipo: Pré-impressão
ENG
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We present CO(1-0) observations of the interacting galaxy system Arp 94, which contains the Seyfert galaxies NGC 3227 and NGC 3226 as well as the star-forming candidate dwarf galaxy J1023+1952. We mapped the CO distribution in J1023+1952 with the IRAM 30m telescope and found molecular gas across the entire extent of the neutral hydrogen cloud ??? an area of about 9 by 6 kpc. The region where star formation (SF) takes place is restricted to a much smaller (??? 1.5 by 3 kpc) region in the south where the narrow line width of the CO shows that the molecular gas is dynamically cold. Neither the molecular nor the total gas surface density in the SF region are signi???cantly higher than in the rest of the object suggesting that an external trigger is causing the SF. The fact that CO is abundant and apparently a good tracer for the molecular gas in J1023+1952 indicates that its metallicity is relatively high and argues for a tidal origin of this object.

La risa transoceánica de Vicente Huidobro y Hans Arp. Ironía y parodia como fundamento de la escritura a cuatro manos de “Tres inmensas novelas”

Gatti, Giuseppe
Fonte: Murcia : Universidad de Murcia, Editum Publicador: Murcia : Universidad de Murcia, Editum
Tipo: Artigo de Revista Científica Formato: application/pdf
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El presente estudio se propone analizar el uso de los procedimientos irónicos y las modalidades discursivas paródicas que Vicente Huidobro utiliza en Tres inmensas novelas, recopilación de tres breves relatos humorísticos que el poeta chileno redactó junto con Hans Arp, en el año 1931, durante un verano compartido en el pueblo de Arcachon, en la región de Aquitania. El primer elemento que se quisiera destacar es la posición geopoética desde la que el texto fue escrito, pues se trata de unas narraciones elaboradas “desde los márgenes”: en el caso de Huidobro la perspectiva des-centrada depende de su procedencia geocultural (ciudadano latinoamericano viviendo en el continente europeo); en el caso de Arp por la condición de desterrado que el artista alsaciano experimentó debido a los continuos enfrentamientos entre Francia y Alemania por el control de la región. Mediante el uso de la parodia, la ironía y la paradoja, los tres breves textos cuestionan toda manifestación de agresividad y toda forma de violencia –tanto física como verbal o ideológica–, utilizando una serie de recursos retóricos que provocan la risa en el lector al mismo tiempo que desatan reflexiones sobre cómo acontecimientos trágicos (una guerra)...

X-ray Emitting QSOs Ejected from Arp 220

Arp, H. C.; Burbidge, E. M.; Chu, Y.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 30/01/2001
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Four compact ROSAT X-ray sources very close to the nearby ultraluminous infrared galaxy Arp 220 (IC 4553) have been identified as medium-redshift QSOs. The closest pair lying symmetrically across the galaxy have almost identical redshifts z = 1.25, 1.26. All of the evidence suggests that these QSOs have been ejected from Arp 220 and have large intrinsic redshifts.; Comment: submitted to ApJ Letters, Figs. 1-3 included as JPEG

The Kinematics of Arp 295 in H-alpha Emission: an Interacting Galaxy with Highly Asymmetric Rotation

Roche, Nathan
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
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We investigate Arp 295, a pair of interacting spirals at z=0.023. We measure scalelengths 5.24 kpc for Arp 295a and 2.52 kpc for 295b. There is a much smaller Im galaxy associated with the larger spiral. Arp 295b is asymmetric with the disk more extended eastwards but with the brightest star-formation regions on the west side of the nucleus. The spectrum of Arp 295b shows strong emission lines with [OII]3727 prominent. We measure the total H-alpha line luminosities of Arp 295b and Arp 295c as 4.69x 10^{41} and 6.76x 10^{40} ergs/s, corresponding to star-formation rates 3.7 and 0.53 solar masses/year. We map the kinematics of Arp 295b in H-alpha with the Manchester Echelle Spectrograph. The maximum disk rotation velocity is 252.6 km/s. The rotation curve of Arp 295b is very asymmetric. The east (approaching) side has a higher radial velocity than the west with the maximum difference 5 arcsec from the nucleus, where it is 88 km/s or a factor 1.675. The slowed rotation on the western side of the nucleus may have locally enhanced star-formation.; Comment: 11 pages, 10 figures, revised version. Rev Mex Ast, in press. To appear vol 43, no. 1, April 2007

A Focused, Hard X-ray Look at Arp 299 with NuSTAR

Ptak, A.; Hornschemeier, A.; Zezas, A.; Lehmer, B.; Yukita, M.; Wik, D.; Antoniou, V.; Argo, M. K.; Ballo, L.; Bechtol, K.; Boggs, S.; Della Ceca, R.; Christensen, F. E.; Craig, W. W.; Hailey, C. J.; Harrison, F. A.; Krivonos, R.; Maccarone, T. J.; Stern,
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 09/12/2014
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27.46%
We report on simultaneous observations of the local starburst system Arp 299 with NuSTAR and Chandra, which provides the first resolved images of this galaxy up to energies of ~ 45 keV. Fitting the 3-40 keV spectrum reveals a column density of $N_{\rm H}$ ~ 4 x10^{24} cm^{-2}, characteristic of a Compton-thick AGN, and a 10-30 keV luminosity of 1.2x 10^{43} ergs s^{-1}. The hard X-rays detected by NuSTAR above 10 keV are centered on the western nucleus, Arp 299-B, which previous X-ray observations have shown to be the primary source of neutral Fe-K emission. Other X-ray sources, including Arp 299-A, the eastern nucleus which is also thought to harbor an AGN, as well as X-ray binaries, contribute $\lesssim 10%$ to the 10-20 keV emission from the Arp 299 system. The lack of significant emission above 10 keV other than that attributed to Arp 299-B suggests that: a) any AGN in Arp 299-A must be heavily obscured ($N_{\rm H}$ > 10^{24} cm^{-2}) or have a much lower luminosity than Arp 299-B and b) the extranuclear X-ray binaries have spectra that cut-off above ~10 keV. Such soft spectra are characteristic of ultraluminous X-ray (ULX) sources observed to date by NuSTAR.; Comment: 9 pages; accepted for publication in Astrophysical Journal

The Far‐Infrared Spectrum of Arp 220

Cernicharo, José; Fischer, Jacqueline; Smith, Howard A.; González‐Alfonso, Eduardo
Fonte: American Astronomical Society Publicador: American Astronomical Society
Tipo: Pre-print Formato: 780910 bytes; application/pdf
ENG
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ISO/LWS grating observations of the ultraluminous infrared galaxy Arp 220 shows absorption in molecular lines of OH, H$_2$O, CH, NH, and NH$_3$, as well as in the [O I] 63 $\mu$m line and emission in the [C II] 158 $\mu$m line. We have modeled the continuum and the emission/absorption of all observed features by means of a non-local radiative transfer code. The continuum from 25 to 1300 $\mu$m is modeled as a warm (106 K) nuclear region that is optically thick in the far-infrared, attenuated by an extended region (size 2$''$) that is heated mainly through absorption of nuclear infrared radiation. The molecular absorption in the nuclear region is characterized by high excitation due to the high infrared radiation density. The OH column densities are high toward the nucleus and the extended region. The H$_2$O column density is also high toward the nucleus and lower in the extended region. The column densities in a halo are similar to what are found in the diffuse clouds toward Sgr B2 near the Galactic Center. Most notable are the high column densities found for NH and NH$_3$ toward the nucleus, with values of $\sim1.5\times10^{16}$ cm$^{-2}$ and $\sim3\times10^{16}$ cm$^{-2}$, respectively. A combination of PDRs in the extended region and hot cores with enhanced \hdo photodissociation and a possible shock contribution in the nuclei may explain the relative column densities of OH and \hdo...

A Focused, Hard X-Ray Look at Arp 299 with NuSTAR

Ptak, A.; Hornschemeier, A.; Zezas, A.; Lehmer, B.; Yukita, M.; Wik, D.; Antoniou, V.; Argo, M. K.; Ballo, L.; Bechtol, K.; Boggs, S.; Della Ceca, R.; Christensen, F. E.; Craig, W. W.; Hailey, C. J.; Harrison, F. A.; Krivonos, R.; Maccarone, T. J.; Stern,
Fonte: American Astronomical Society Publicador: American Astronomical Society
Tipo: Article; PeerReviewed Formato: application/pdf; application/pdf
Publicado em 20/02/2015
Relevância na Pesquisa
27.46%
We report on simultaneous observations of the local starburst system Arp 299 with NuSTAR and Chandra, which provides the first resolved images of this galaxy up to energies of ~45 keV. Fitting the 3-40 keV spectrum reveals a column density of N_H ~ 4 × 10^(24) cm^(–2), characteristic of a Compton-thick active galactic nucleus (AGN), and a 10-30 keV luminosity of 1.2 × 10^(43) erg s^(–1). The hard X-rays detected by NuSTAR above 10 keV are centered on the western nucleus, Arp 299-B, which previous X-ray observations have shown to be the primary source of neutral Fe-K emission. Other X-ray sources, including Arp 299-A, the eastern nucleus also thought to harbor an AGN, as well as X-ray binaries, contribute ≾ 10% to the 10-20 keV emission from the Arp 299 system. The lack of significant emission above 10 keV other than that attributed to Arp 299-B suggests that: (1) any AGN in Arp 299-A must be heavily obscured (N_H > 10^(24) cm^(–2)) or have a much lower luminosity than Arp 299-B and (2) the extranuclear X-ray binaries have spectra that cut-off above ~10 keV. Such soft spectra are characteristic of ultraluminous X-ray sources observed to date by NuSTAR.

The Kinematics of ARP 295 in Hα Emission: An Interacting Galaxy with Highly Asymmetric Rotation

Roche,Nathan
Fonte: Instituto de Astronomía, UNAM Publicador: Instituto de Astronomía, UNAM
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2007 EN
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We investigate Arp 295, a pair of interacting spirals at z = 0.023, using optical spectroscopy, Ha imaging, and Ha velocity mapping with the Manchester Echelle Spectrograph. Scalelengths are r exp = 5.24 for Arp 295a and 2.52 kpc for 295b. A much smaller Im galaxy, Arp 295c, is associated with the larger spiral. Arp 295b is asymmetric with the disk more extended eastwards but with the brightest star-formation regions on its western side. The spectrum of Arp 295b shows strong emission lines with [OII] 3727 equivalent width 36Å. The total Hα luminosities of Arp 295b and Arp 295c are 4.69 x 10(41) and 6.76 x 10(40) ergs s-1, corresponding to star-formation rates 3.7 and 0.53 yr -1. For Arp 295b, we measure the maximum disk rotation velocity as 252.6 ± 9.9 km s -1 and find the rotation curve is very asymmetric. The east (approaching) side has a higher radial velocity than the west with the maximum difference (at r = 5 arcsec) of 88 km s -1, or a factor 1.675.