Innermost Parts Research Articles

Profiled spectral lines generated in the field of Kerr superspinars

String Theory suggests existence of primordial Kerr superspinars, extremely compact objects with external spacetime described by the Kerr naked singularity geometry. The primordial Kerr superspinars have to be converted to a near-extreme black hole due to accretion, but they could survive to the era of highly redshifted quasars. We study the shape of the profiled spectral lines generated by radiating rings or the innermost parts of Keplerian discs orbiting the Kerr superspinars. Influence of the superspinar surface location on the profiled lines is also considered. We demonstrate strong difference of the character of the profiled lines generated by radiating rings for all values of the superspinar spin and all values of the inclination angles of the observer when compared to those generated in the field of Kerr black holes. For small and mediate inclination angles there are large quantitative differences in the extension and position of the lines. For large inclination angles even strong qualitative difference appears as the profiled lines have a clear doubled character. The smaller, redshifted region of the profiled line is related to the photons reaching the regions near the superspinar surface. Strong differences are obtained also for profiled lines generated by the innermost parts of Keplerian discs especially in the shape of the line. The influence of the superspinar surface location is reflected in the intermediate parts of the the profiled lines. The line profiles can give a clear signature of the presence of a Kerr superspinar and in principle enable estimates of its surface location since the signatures of the superspinar surface location are of different character as those corresponding to the presence of the black hole horizon.

Hot accretion flow in black hole binaries: a link connecting X-rays to the infrared

Multiwavelength observations of Galactic black hole transients have opened a new path to understanding the physics of the innermost parts of the accretion flows. While the processes giving rise to their X-ray continuum have been studied extensively, the emission in the optical and infrared (OIR) energy bands was less investigated and remains poorly understood. The standard accretion disc, which may contribute to the flux at these wavelengths, is not capable of explaining a number of observables: the infrared excesses, fast OIR variability and a complicated correlation with the X-rays. It was suggested that these energy bands are dominated by the jet emission; however, this scenario does not work in a number of cases. We propose here an alternative, namely that most of the OIR emission is produced by the extended hot accretion flow. In this scenario, the OIR bands are dominated by the synchrotron radiation from the non-thermal electrons. An additional contribution is expected from the outer irradiated part of the accretion disc heated by the X-rays. We discuss the properties of the model and compare them to the data. We show that the hot-flow scenario is consistent with many of the observed spectral data, at the same time naturally explaining X-ray timing properties, fast OIR variability and its correlation with the X-rays.

ALMA 690 GHz OBSERVATIONS OF IRAS 16293–2422B: INFALL IN A HIGHLY OPTICALLY THICK DISK

We present sensitive, high angular resolution ($\sim$ 0.2 arcsec) submillimeter continuum and line observations of IRAS 16293-2422B made with the Atacama Large Millimeter/Submillimeter Array (ALMA). The 0.45 mm continuum observations reveal a single and very compact source associated with IRAS 16293-2422B. This submillimeter source has a deconvolved angular size of about 400 {\it milli-arcseconds} (50 AU), and does not show any inner structure inside of this diameter. The H$^{13}$CN, HC$^{15}$N, and CH$_{3}$OH line emission regions are about twice as large as the continuum emission and reveal a pronounced inner depression or "hole" with a size comparable to that estimated for the submillimeter continuum. We suggest that the presence of this inner depression and the fact that we do not see inner structure (or a flat structure) in the continuum is produced by very optically thick dust located in the innermost parts of IRAS 16293-2422B. All three lines also show pronounced inverse P-Cygni profiles with infall and dispersion velocities larger than those recently reported from observations at lower frequencies, suggesting that we are detecting faster, and more turbulent gas located closer to the central object. Finally, we report a small east-west velocity gradient in IRAS 16293-2422B that suggests that its disk plane is likely located very close to the plane of the sky.

ON THE EFFECTS OF OPTICALLY THICK GAS (DISKS) AROUND MASSIVE STARS

Numerical simulations have shown that the often cited radiation pressure barrier to accretion onto massive stars can be circumvented, when the radiation field is highly anisotropic in the presence of a circumstellar accretion disk with high optical depth. Here, these studies of the so-called flashlight effect are expanded by including the opacity of the innermost dust-free but potentially optically thick gas regions around forming massive stars. In addition to frequency-dependent opacities for the dust grains, we use temperature- and density-dependent Planck- and Rosseland mean opacities for the gas. The simulations show that the innermost dust-free parts of the accretion disks are optically thick to the stellar radiation over a substantial fraction of the solid angle above and below the disk's midplane. The temperature in the shielded disk region decreases faster with radius than in a comparison simulation with a lower constant gas opacity, and the dust sublimation front is shifted to smaller radii. The shielding by the dust-free gas in the inner disk thus contributes to an enhanced flashlight effect, which ultimately results in a smaller opening angle of the radiation pressure driven outflow and in a much longer timescale of sustained feeding of the circumstellar disk by the molecular cloud core. We conclude that it is necessary to properly account for the opacity of the inner dust-free disk regions around forming massive stars in order to correctly assess the effectiveness of the flashlight effect, the opening angle of radiation pressure driven outflows, and the lifetime and morphological evolution of the accretion disk.

外来二枚貝コウロエンカワヒバリガイの日本海沿岸での分布

The distribution of the non-indigenous mytilid bivalve Xenostrobus securis (Lamarck, 1819), native to Australasia, was investigated through a survey of 325 sites along the Japanese coast of the Sea of Japan from 2006 to 2011. The species was found at 20 sites from Toyama Prefecture westwards (Toyama Port and Shin-minato Fishing Port in Toyama Prefecture; Kanazawa Port and the Daishoji River in Ishikawa Prefecture; the Inokuchi River, Lake Kugushi, and Lake Suigetsu in Fukui Prefecture; the Takeno River in Hyogo Prefecture; Lake Nakaumi in Tottori and Shimane Prefectures; and Dokai Bay and Hakata Bay in Fukuoka Prefecture), all of which were located in brackish-water areas such as lagoons, river mouths, and the innermost parts of large ports. Size distributions of the collected mussels suggest that breeding populations have been established at eight sites. Although X. securis was not found at 86 sites from Niigata Prefecture northwards, water temperature regimes in the native and invaded areas suggest that it may eventually spread as far north as the southern end of Hokkaido.

Modeling optical and UV polarization of AGNs

We model the spectropolarimetric signature resulting from the radiative coupling between the innermost parts of active galactic nuclei (AGNs). We use a new public version of STOKES, a Monte Carlo radiative transfer code presented in the first paper of this series. The code has been significantly improved for computational speed and polarization imaging has been implemented. We couple continuum sources with equatorial scattering regions, polar outflows, and toroidal obscuring dust and we study the resulting polarization. We compute a grid of thermal AGN models for different half-opening angles of the torus and polar winds. We also consider a range of optical depths for equatorial and polar electron scattering and investigate how the model geometry influences the type-1/type-2 polarization dichotomy for thermal AGNs. We put new constrains on the inflowing medium within the inner walls of the torus. The inflow should be confined to the common equatorial plane of the torus and the accretion disc and have a radial optical depth of 1 < tau < 3. Our modeling of type-1 AGNs also indicates that the torus is more likely to have a large (~ 60{\deg}) half-opening angle. Polarization perpendicular to the axis of the torus may arise at a type-1 viewing angle for a torus half-opening angle of 30{\deg}- 45{\deg} or polar outflows with an optical depth near unity. Our modeling suggests that most Seyfert-2 AGN must have a half-opening angle > 60{\deg} to match the level of perpendicular polarization expected. If outflows are collimated by the torus inner walls, they must not be optically thick (tau < 1) in order to preserve the polarization dichotomy. The wind's optical depth is found not to play a critical role for the degree of polarization of type-2 thermal AGNs but it has a significant impact on the type-1/type-2 polarization dichotomy when the optical depth exceeds tau = 0.3.

X-ray variations in the inner accretion flow of dwarf novae

We show for five DN systems, SS Cyg, VW Hyi, RU Peg, WW Cet and T Leo that the UV and X-ray power spectra of their time variable light curves are similar in quiescence. All of them show a break in their power spectra, which in the framework of the model of propagating fluctuations indicates inner disk truncation. We derive the inner disk radii for these systems in a range (10-3)$\times10^{9}$ cm. We analyze the RXTE data of SS Cyg in outburst and compare it with the power spectra, obtained during the period of quiescence. We show that during the outburst the disk moves towards the white dwarf and recedes as the outburst declines. We calculate the correlation between the simultaneous UV and X-ray light curves of the five DN studied in this work, using the XMM-Newton data obtained in the quiescence and find X-ray time lags of 96-181 sec. This can be explained by the travel time of matter from a truncated inner disk to the white dwarf surface. We suggest that, in general, DN may have truncated accretion disks in quiescence which can also explain the UV and X-ray delays in the outburst stage and that the accretion may occur through coronal flows in the disk (e.g., rotating accretion disk coronae). Within a framework of the model of propagating fluctuations the comparison of the X-ray/UV time lags observed by us in the case of DN systems with those, detected for a magnetic Intermediate Polar allows us to make a rough estimate of the viscosity parameter $\alpha\sim0.25$ in the innermost parts of the accretion flow of DN systems.

MILKY WAY SUPERMASSIVE BLACK HOLE: DYNAMICAL FEEDING FROM THE CIRCUMNUCLEAR ENVIRONMENT

The supermassive black hole (SMBH), Sgr A*, at the Galactic Center is surrounded by a molecular circumnuclear disk (CND) lying between 1.5-4 pc radii. The irregular and clumpy structures of the CND, suggest dynamical evolution and episodic feeding of gas towards the central SMBH. New sensitive data from the SMA and GBT, reveal several >5-10 pc scale molecular arms, which either directly connect to the CND, or may penetrate inside the CND. The CND appears to be the convergence of the innermost parts of largescale gas streamers, which are responding to the central gravitational potential well. Rather than being a quasi-stationary structure, the CND may be dynamically evolving, incorporating inflow via streamers, and feeding gas towards the center.

Jet-linked X-ray emission in radio-loud broad absorption line (BAL) quasars

AbstractWe have applied theoretical models to explain spectral energy distribution (SED) of three radio-loud broad absorption line (BAL) quasars: an extended hybrid object PG 1004+130 and two compact sources 1045+352 and 3C270.1. We calculate the emission from the very inner part of the sources which accounts for more than 90% of the observed X-ray radiation. In our analysis we consider a scenario in which the observed X-ray emission comes from the inverse-Compton (IC) scattering inside a jet and from the accretion disk corona. The compact objects 1045+352 and 3C270.1 are high-redshift quasars (z = 1.604 and 1.532 respectively), with strong radio cores. We argue that in the case of these two sources a non-thermal, inverse-Compton emission from the innermost parts of the jet can explain a large fraction of the observed X-ray emission. The large scale object PG 1004+130 with a peculiar radio morphology is a low-redshift (z = 0.24), lobe-dominated BAL quasar with a weak radio core. In this case simulated inverse-Compton X-ray emission of the jet is relatively low. However, the corona emission appears strong enough to explain the observed X-ray spectrum of this object.

An Attempt to Describe Frequency Correlations among kHz QPOs and HBOs by Two-Armed Nearly Vertical Oscillations

We examine whether the two-armed ($m$$=$ 2) vertical p-mode oscillations trapped in the innermost region of magnetized accretion disks with finite disk thickness can describe kHz quasi-periodic oscillations (QPOs) and horizontal branch oscillations (HBOs) in low-mass X-ray binaries (LMXBs). First, we derive the frequency–frequency correlation of the two basic oscillations (both are fundamental modes in the vertical direction, but one is the fundamental and the other the first overtone in the radial direction), and compare it with the observed frequency correlation of twin kHz QPOs. Results show that the calculated frequency correlation can well describe the observed frequency one with reasonable values of the parameters. Second, we examine whether the observed frequency correlation between kHz QPOs and HBO can be described by regarding HBO as the first overtone oscillation in the vertical direction (and the fundamental in the radial direction). The results suggest that (i) the innermost parts of disks on the horizontal branch are strongly diminished in their vertical thickness (presumably by hot coronae) and (ii) the branch is roughly a sequence of variations of magnetic fields or disk temperature.

Topochemical and transmission electron microscopic studies of bacterial decay in pine (Pinus sylvestris L.) harbour foundation piles

Bacterial degradation of Pinus sylvestris harbour foundation piles was studied topochemically by scanning UV-microspectrophotometry. This analytical technique enables direct imaging of lignin distribution within individual cell wall layers. Additionally, light and transmission electron microscopy (TEM) was used to characterise structural changes of the cell walls. Various decay stages were found in the samples. TEM revealed that the bacterial degradation occurred mainly in the S2, leaving granular remnants in degraded wall portions with lower as well as higher electron density than the surrounding unmodified wall. In the initial stages, topochemical investigations revealed that lignin modification starts in the innermost parts of the secondary wall, most clearly observed in latewood tracheids. During advanced degradation, lignin modification occurs more or less severe in walls of all cell types. However, even in cell portions with intensive decay, the compound middle lamellae and ray tracheids were undegraded. The knowledge about lignin modification at initial stages of wood degradation by bacteria is of fundamental importance to provide more information on the process of cell wall decay.

The Cell and Molecular Biology of Glaucoma: Mechanisms in the Conventional Outflow Pathway

Glaucoma, a blinding disease that affects millions in the United States, is treatable. Multiple clinical trials involving thousands of patients have repeatedly shown that lowering intraocular pressure (IOP) saves vision in those with glaucoma. In fact, if IOP in those with glaucoma is lowered sufficiently, vision loss dramatically slows—nearly stopping. IOP is a function of the balance of fluid (aqueous humor) entering and leaving the eye. Although there are very good medications that lower IOP by decreasing fluid production by the inflow pathway and increasing fluid egress via the secondary outflow pathway, unfortunately there is not a daily medication that enhances outflow through the primary outflow route: the conventional pathway. The conventional outflow pathway is the tissue that becomes diseased and is responsible for ocular hypertension (elevated IOP) in those with glaucoma. 1 Consequently, persons with glaucoma have elevated IOP and higher resistance to outflow than do those of similar age without glaucoma. Although this extra resistance to outflow can be removed surgically to bypass the dysfunctional tissue, a primary focus of glaucoma research is to understand the molecular and cellular mechanisms that control resistance, so that medications can be developed that can lower resistance and return function to the conventional outflow pathway. The conventional (or trabecular) outflow pathway has a fascinating design (Fig. 1). Fluid flow through the tissue and out of the eye is driven by a pressure gradient across the tissue. Thus, the pressure difference inside (IOP) and outside (episcleral venous pressure [EVP]) the eye moves aqueous humor through an area that functions like a filter positioned in front of a region that acts like a resistor. The cell surfaces in the innermost parts of the trabecular meshwork (TM) tissue act like a filter, removing cell debris, pigment, and reactive oxygen species from aqueous humor before it reaches (and has the opportunity to clog) the resistant part of the pathway located near the inner wall of Schlemm’s canal (SC), called the juxtacanalicular (JCT) region. Resistance to outflow is generated in the JCT region of the conventional pathway and most likely involves a funneling mechanism. 2 Hence, resistance due to funneling is a function of two parameters: (1) spacing in the JCT due to the interaction between TM cells and inner wall cells of SC and (2) the number of openings (pores) in the inner wall. The theory is that as fluid moves through the TM and approaches the inner wall, it is funneled toward the pores in the inner wall, creating a bottleneck that generates resistance and thus IOP. MOLECULAR AND CELLULAR TARGETS IN THE CONVENTIONAL OUTFLOW PATHWAY If most of the fluid leaves the eye by way of (and pathology resides in) the conventional outflow pathway, then why is there no daily medication for glaucoma patients that targets conventional outflow? The simple answer is that the conventional outflow system is complicated, with many backup and compensatory mechanisms, keeping IOP within a very narrow range (usually, 2 mm Hg) in most people throughout life. Moreover, it appears that autoregulatory systems in the conventional pathway are geared toward preventing IOP from descending below a critical level, no matter how effective current medications affect inflow and the secondary outflow route in glaucoma patients. Such a design is probably due to a biological tolerance for elevated IOP, but not for reduced IOP, which may destabilize the ocular structures from the visual axis of the eye and disrupt vision.

Observational phenomena related to primordial Kerr superspinars

String theory indicates the existence of primordial Kerr superspinars, extremely compact objects with exterior described by the Kerr naked-singularity geometry. The primordial superspinars have to be converted to a black hole due to accretion, but they could survive to the era of high-redshift quasars. We discuss observational phenomena caused by the primordial Kerr superspinars in this era, considering the properties of corotating Keplerian accretion discs orbiting such superspinars and the optical phenomena modified by their presence. The potential well around a near-extreme superspinar with spin a very close to the extreme black hole value a = 1 is very deep so that the efficiency of the accretion process reaches 157.7%, influencing thus significantly the spectral continuum of corotating Keplerian discs and giving a signature of near-extreme superspinars. Such superspinars can also serve as an efficient accelerator for extremely high-energy collisions. Phenomena enabling a clear distinction of primordial Kerr superspinars and black holes are related to the disc oscillations with the radial and vertical epicyclic frequencies and the most profound could be differences implied by the profiled spectral lines generated in the innermost parts of the corotating Keplerian discs.

Counter-rotating Keplerian discs around Kerr superspinars

The appearance of corotating Keplerian discs orbiting Kerr superspinars has been shown to be strongly dependent on the value of the superspinar spin in both their shape and frequency shift profile, demonstrating clear distinctions from the corotating discs around black holes. However, it has to be modified in the innermost parts of the disc by the self-illumination effect caused by the photons trapped in the strong gravitational field near the superspinars with spin a < 9. Here we demonstrate that self-illumination is irrelevant for counter-rotating Keplerian discs orbiting in the field of all Kerr superspinars since such discs are located at the regions where none of the radiated photons can be trapped. Therefore, the results obtained by considering the escaping photons only are quite relevant for the appearance of the counter-rotating Keplerian discs orbiting Kerr superspinars. The appearance and spectral continuum of such discs differ from those of counter-rotating discs in the field of Kerr black holes. The differences are of quantitative character except the existence of the disc images located inside the image of the inner edge of the disc that are created by photons reaching regions close to the surface of Kerr superspinars. Their observational relevance is realistic in the near future for accretion phenomena in the vicinity of Sgr A*.

Coastal pollution monitoring: Foraminifera as tracers of environmental perturbation in the port of Boulogne-sur-Mer (Northern France)

Abstract: Benthic foraminifera are increasingly used as environmental indicators of natural and/ or anthropogenic stress in coastal and marginal marine settings. A study of both living (Rose Bengal stained) and dead foraminifera was carried on 317 sediment samples collected in the port of Boulogne-sur-Mer (France). Here we present an initial status report on the port ecosystem as recorded from a selected set of sediment samples that cover the full range of habitats within the port. A surprisingly high diversity assemblage of benthic foraminifera was recovered, reflecting the varied habitats within the port. Among the total of 82 species recorded, 34 were found alive (rose Bengal stained). Four key species were identified as potential bioindicators and analyzed with regard to their distribution and correspondence with environmental parameters (sediment grain size, organic carbon content and heavy metal concentration, Cr, Cu and Zn). The benthic foraminifera Haynesina germanica and Bolivina pseudoplicata were found to live particularly well within the innermost parts of the port basins where the highest concentrations of organic carbon and heavy metals occur. Elphidium excavatum and E. magellanicum are well represented in the external parts of the port and can be considered as indicators that tolerate certain threshold values of pollution and environmental stress. As the port is located in an estuarine setting, the relationship between the key indicator taxa for pollution and natural environment is discussed. This study emphasizes the need to address the anthropogenic impact on coastal environments by screening the ubiquitous record of foraminiferal protists as precision tools for bio-monitoring.

Prospect of polarization measurements from black hole binaries in their thermal state with a scattering polarimeter

X-ray polarization measurement is a unique tool which may provide crucial information regarding the emission mechanism and the geometry of various astrophysical sources, such as neutron stars, accreting black holes, pulsar wind nebulae, active galactic nuclei, supernova remnants etc., and can help us to probe matter under extreme magnetic fields and extreme gravitational fields. Although the three other domains of X-ray astronomy, i.e. timing, spectral and imaging are well developed, there has been very little progress in X-ray polarimetry with only one definitive polarization measurement and a few upper limits available so far. Radiation from accreting black holes in their thermal-dominated (high soft) state is expected to be polarized due to scattering in the plane-parallel atmosphere of the disc. Furthermore, special and general relativistic effects in the innermost parts of the disc predict energy-dependent rotation in the plane of polarization and some distinct signatures which can be used as a probe for measuring the parameters of the black hole, like its spin, emissivity profile and the angle of inclination of the system. We present the results from an analysis of expected minimum detectable polarization from some of the galactic black hole binaries, GRO J1655−40, GX 339−4, H1743−322, Cygnus X-1 and XTE J1817−330, in their thermal-dominated state with a proposed Thomson X-ray polarimeter. A proposal for a scattering polarimeter has been submitted to the Indian Space Research Organization for a dedicated small satellite mission and a laboratory unit has been built. Along with the measurement of the degree of polarization, the polarization angle measurement is also important, hence the error in the polarization angle measurement for a range of detection significance is also obtained.

Gravitationally lensed QSOs in the ISSIS/WSO-UV era

Gravitationally lensed QSOs (GLQs) at 1≤z≤2 play a key role in understanding the cosmic evolution of the innermost parts of active galaxies (black holes, accretion disks, coronas and internal jets), as well as the structure of galaxies at intermediate redshifts. With respect to studies of normal QSOs, GLQ programmes have several advantages. For example, a monitoring of GLQs may lead to unambiguous detections of intrinsic and extrinsic variations. Both kinds of variations can be used to discuss central engines in distant QSOs, and mass distributions and compositions of lensing galaxies. In this context, UV data are of particular interest, since they correspond to emissions from the immediate surroundings of the supermassive black hole. We describe some observation strategies to analyse optically bright GLQs at z∼1.5, using ISSIS (CfS) on board World Space Observatory-Ultraviolet.

Substrate recognition and translocation by polyspecific organic cation transporters

Organic cation transporters (OCTs) of the SLC22 family play a pivotal role in distribution and excretion of cationic drugs. They mediate electrogenic translocation of cations in both directions. OCTs are polyspecific transporters. During substrate translocation they perform a series of conformational changes involving an outward-facing conformation, an occluded state and an inward-facing conformation. Mutagenesis of OCT1 in combination with homology modeling showed that identical amino acids form the innermost parts of the outward-open and inward-open binding clefts. In addition to low affinity substrate binding sites, OCT1 contains high affinity substrate binding sites that can mediate inhibition via non-transported compounds.

CS LINE PROFILES IN HOT CORES

We present a theoretical study of CS line profiles in archetypal hot cores. We provide estimates of line fluxes from the CS(1-0) to the CS(15-14) transitions and present the temporal variation of these fluxes. We find that \textit{i)} the CS(1-0) transition is a better tracer of the Envelope of the hot core whereas the higher-J CS lines trace the ultra-compact core; \textit{ii)} the peak temperature of the CS transitions is a good indicator of the temperature inside the hot core; \textit{iii)} in the Envelope, the older the hot core the stronger the self-absorption of CS; \textit{iv)} the fractional abundance of CS is highest in the innermost parts of the ultra-compact core, confirming the CS molecule as one of the best tracers of very dense gas.

EXTREMELY LARGE AND HOT MULTILAYER KEPLERIAN DISK AROUND THE O-TYPE PROTOSTAR W51N: THE PRECURSORS OF THE HCH II REGIONS?

We present sensitive high angular resolution (0.57$''$-0.78$''$) SO, SO$_2$, CO, C$_2$H$_5$OH, HC$_3$N, and HCOCH$_2$OH line observations at millimeter and submillimeter wavelengths of the young O-type protostar W51 North made with the Submillimeter Array (SMA). We report the presence of a large (of about 8000 AU) and hot molecular circumstellar disk around this object, which connects the inner dusty disk with the molecular ring or toroid reported recently, and confirms the existence of a single bipolar outflow emanating from this object. The molecular emission from the large disk is observed in layers with the transitions characterized by high excitation temperatures in their lower energy states (up to 1512 K) being concentrated closer to the central massive protostar. The molecular emission from those transitions with low or moderate excitation temperatures are found in the outermost parts of the disk and exhibits an inner cavity with an angular size of around 0.7$''$. We modeled all lines with a Local Thermodynamic Equilibrium (LTE) synthetic spectra. A detail study of the kinematics of the molecular gas together with a LTE model of a circumstellar disk shows that the innermost parts of the disk are also Keplerian plus a contracting velocity. The emission of the HCOCH$_2$OH reveals the possible presence of a warm ``companion'' located to the northeast of the disk, however its nature is unclear. The emission of the SO and SO$_2$ is observed in the circumstellar disk as well as in the outflow. We suggest that the massive protostar W51 North appears to be in a phase before the presence of a Hypercompact or an Ultracompact HII (HC/UCHII) region, and propose a possible sequence on the formation of the massive stars.