- ID:
- ivo://CDS.VizieR/J/A+A/641/A102
- Title:
- Milky Way nuclear star cluster HKs photometry
- Short Name:
- J/A+A/641/A102
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The environment of Sagittarius A* (Sgr A*), the central black hole of the Milky Way, is the only place in the Universe where we can currently study the interaction between a nuclear star cluster and a massive black hole and infer the properties of a nuclear cluster from observations of individual stars. This work aims to explore the star formation history of the nuclear cluster and the structure of the innermost stellar cusp around Sgr A*. We combined and analysed multi epoch high quality AO observations. For the region close to Sgr A* we apply the speckle holography technique to the AO data and obtain images that are >=50% complete down to Ks~19 within a projected radius of 5" around Sgr A*. We used $H$-band images to derive extinction maps. We provide Ks photometry for roughly 39000 stars and H-band photometry for ~11000 stars within a field of about 40"x40", centred on Sgr A*. In addition, we provide Ks photometry of ~3000 stars in a very deep central field of 10"x10", centred on Sgr A*. We find that the Ks luminosity function (KLF) is rather homogeneous within the studied field and does not show any significant changes as a function of distance from the central black hole on scales of a few 0.1pc. By fitting theoretical luminosity functions to the KLF, we derive the star formation history of the nuclear star cluster. We find that about 80% of the original star formation took place 10Gyr ago or longer, followed by a largely quiescent phase that lasted for more than 5Gyr. We clearly detect the presence of intermediate-age stars of about 3Gyr in age. This event makes up about 15% of the originally formed stellar mass of the cluster. A few percent of the stellar mass formed in the past few 100Myr. Our results appear to be inconsistent with a quasi-continuous star formation history. The mean metallicity of the stars is consistent with being slightly super solar. The stellar density increases exponentially towards Sgr A* at all magnitudes between Ks=15-19. We also show that the precise properties of the stellar cusp around Sgr A* are hard to determine because the star formation history suggests that the star counts can be significantly contaminated, at all magnitudes, by stars that are too young to be dynamically relaxed. We find that the probability of observing any young (non-millisecond) pulsar in a tight orbit around Sgr A* and beamed towards Earth is very low. We argue that typical globular clusters, such as they are observed in and around the Milky Way today, have probably not contributed to the nuclear cluster's mass in any significant way. The nuclear cluster may have formed following major merger events in the early history of the Milky Way.
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/476/1243
- Title:
- Millimeter continuum mapping of Cygnus X
- Short Name:
- J/A+A/476/1243
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report on a millimeter continuum survey of the entire Cygnus X molecular complex. We used the MAMBO and MAMBO-2 bolometer arrays on the IRAM 30m telescope to map a 3deg^2^ area at 1.2mm (see fits files of Figures 2, kept to 11" resolution). Our MAMBO-2 imaging gives a complete view of the cloud structures ranging from 0.03pc to 5pc, i.e. from dense cores to clumps. We perform a multi-resolution analysis to extract 129 compact dense cores (~0.1pc, see Table 1) and identify 40 massive large-scale clumps (~0.7pc, see Table 2). The 21um fluxes arising from dense cores are taken from the MSX point source catalog (MSX C6, Cat. <V/114>).
- ID:
- ivo://CDS.VizieR/J/ApJ/676/427
- Title:
- MIPS and IRAC data on ChaII PMS stars
- Short Name:
- J/ApJ/676/427
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We discuss the results from the combined IRAC and MIPS c2d Spitzer Legacy survey observations and complementary optical and NIR data of the Chamaeleon II (Cha II) dark cloud. We perform a census of the young population in an area of ~1.75deg^2^ and study the spatial distribution and properties of the cloud members and candidate pre-main-sequence (PMS) objects and their circumstellar matter. Our census is complete down to the substellar regime (M~0.03M_{sun}).
- ID:
- ivo://CDS.VizieR/J/AJ/149/64
- Title:
- MIPSGAL 24{mu}m point source catalog
- Short Name:
- J/AJ/149/64
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this contribution, we describe the applied methods to construct a 24{mu}m based point source catalog derived from the image data of the MIPSGAL 24{mu}m Galactic Plane Survey and the corresponding data products. The high quality catalog product contains 933818 sources, with a total of 1353228 in the full archive catalog. The source tables include positional and photometric information derived from the 24{mu}m images, source quality and confusion flags, and counterpart photometry from matched 2MASS, GLIMPSE, and WISE point sources. Completeness decay data cubes are constructed at 1' angular resolution that describe the varying background levels over the MIPSGAL field and the ability to extract sources of a given magnitude from this background. The completeness decay cubes are included in the set of data products. We present the results of our efforts to verify the astrometric and photometric calibration of the catalog, and present several analyses of minor anomalies in these measurements to justify adopted mitigation strategies.
- ID:
- ivo://CDS.VizieR/J/ApJ/672/558
- Title:
- MIPS observations of h and {chi} Persei
- Short Name:
- J/ApJ/672/558
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We describe Spitzer MIPS observations of the double cluster, h and {chi} Persei, covering a ~0.6deg^2^ area surrounding the cores of both clusters. The data are combined with IRAC and 2MASS data to investigate ~616 sources from 1.25-24um. We use the long-baseline Ks-[24] color to identify two populations with IR excess indicative of circumstellar material: Be stars with 24um excess from optically thin free-free emission, and 17 fainter sources (J~14-15) with [24] excess consistent with a circumstellar disk. The frequency of IR excess for the fainter sources increases from 4.5 to 24um. The IR excess is likely due to debris from the planet formation process. The wavelength-dependent behavior is consistent with an inside-out clearing of circumstellar disks. A comparison of the 24um excess population in h and {chi} Per sources with results for other clusters shows that 24um emission from debris disks "rises" from 5 to 10Myr, peaks at ~10-15Myr, and then "falls" from ~15-20Myr to 1Gyr.
- ID:
- ivo://CDS.VizieR/J/MNRAS/423/197
- Title:
- MIPS photometry for Herschel SAG2 Programs
- Short Name:
- J/MNRAS/423/197
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We provide an overview of ancillary 24, 70, and 160 micron data from the Multiband Imaging Photometer for Spitzer (MIPS) that are intended to complement the 70-500 micron Herschel Space Observatory photometry data for nearby galaxies obtained by the Herschel-SPIRE Local Galaxies Guaranteed Time Programs and the Herschel Virgo Cluster Survey. The MIPS data can be used to extend the photometry to wave bands that are not observed in these Herschel surveys and to check the photometry in cases where Herschel performs observations at the same wavelengths. Additionally, we measured globally-integrated 24-160 micron flux densities for the galaxies in the sample that can be used for the construction of spectral energy distributions. Using MIPS photometry published by other references, we have confirmed that we are obtaining accurate photometry for these galaxies.
- ID:
- ivo://CDS.VizieR/J/ApJS/191/212
- Title:
- MIPS sources near the South Ecliptic Pole
- Short Name:
- J/ApJS/191/212
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have imaged an 11.5deg^2^ region of sky toward the South Ecliptic Pole (SEP; J0443-5340) at 24 and 70um with MIPS, the Multiband Imaging Photometer for Spitzer. This region is coincident with a field mapped at longer wavelengths by AKARI and BLAST. We discuss our data reduction and source extraction procedures. The median 1{sigma} depths of the maps are 47uJy/beam at 24um and 4.3mJy/beam at 70um. At 24um, we identify 93098 point sources with signal-to-noise ratio (S/N)>=5 and an additional 63 resolved galaxies; at 70um we identify 891 point sources with S/N>=6. From simulations, we determine a false detection rate of 1.8% (1.1%) for the 24um (70um) catalog. The 24 and 70um point-source catalogs are 80% complete at 230uJy and 11mJy, respectively.
1388. MIPS 24um calibrators
- ID:
- ivo://CDS.VizieR/J/PASP/119/994
- Title:
- MIPS 24um calibrators
- Short Name:
- J/PASP/119/994
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the stellar calibrator sample and the conversion from instrumental to physical units for the 24{mu}m channel of the Multiband Imaging Photometer for Spitzer (MIPS). The primary calibrators are A stars, and the calibration factor based on those stars is 4.54x10^-2^MJy/sr/(DN/s), with a nominal uncertainty of 2%. We discuss the data reduction procedures required to attain this accuracy; without these procedures, the calibration factor obtained using the automated pipeline at the Spitzer Science Center is 1.6%+/-0.6% lower. We extend this work to predict 24{mu}m flux densities for a sample of 238 stars that covers a larger range of flux densities and spectral types. We present a total of 348 measurements of 141 stars at 24{mu}m. This sample covers a factor of ~460 in 24{mu}m flux density, from 8.6mJy up to 4.0Jy. We show that the calibration is linear over that range with respect to target flux and background level. The calibration is based on observations made using 3s exposures; a preliminary analysis shows that the calibration factor may be 1% and 2% lower for 10 and 30s exposures, respectively. We also demonstrate that the calibration is very stable: over the course of the mission, repeated measurements of our routine calibrator, HD 159330, show a rms scatter of only 0.4%. Finally, we show that the point-spread function (PSF) is well measured and allows us to calibrate extended sources accurately; Infrared Astronomy Satellite (IRAS) and MIPS measurements of a sample of nearby galaxies are identical within the uncertainties.
1389. MIPS 24um nebulae
- ID:
- ivo://CDS.VizieR/J/MNRAS/405/1047
- Title:
- MIPS 24um nebulae
- Short Name:
- J/MNRAS/405/1047
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Massive evolved stars lose a large fraction of their mass via copious stellar wind or instant outbursts. During certain evolutionary phases, they can be identified by the presence of their circumstellar nebulae. In this paper, we present the results of a search for compact nebulae (reminiscent of circumstellar nebulae around evolved massive stars) using archival 24um data obtained with the Multiband Imaging Photometer for Spitzer. We have discovered 115 nebulae, most of which bear a striking resemblance to the circumstellar nebulae associated with luminous blue variables (LBVs) and late WN-type (WNL) Wolf-Rayet (WR) stars in the Milky Way and the Large Magellanic Cloud (LMC).
- ID:
- ivo://CDS.VizieR/J/ApJ/723/1110
- Title:
- MIPS 24um observations of the HDFS
- Short Name:
- J/ApJ/723/1110
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present MIPS 24um observations of the Hubble Deep Field South taken with the Spitzer Space Telescope. The resulting image is 254arcmin^2^ in size and has a sensitivity ranging between ~12 and ~30uJy rms, with a median sensitivity of ~20uJy rms. A total of 495 sources have been catalogued with a signal-to-noise ratio greater than 5{sigma}. The source catalog is presented as well as source counts which have been corrected for completeness and flux boosting. The IR sources are then combined with MUSYC optical/NIR and ATHDFS radio observations to obtain redshifts and radio flux densities of the sample. We use the IR/radio flux density ratio (q_24_) to explore the IR-radio correlation for this IR sample and find q_24_=0.71+/-0.31 for sources detected in both IR and radio. The results are extended by stacking IR sources not detected in the radio observations and we derive an average q_24_ for redshift bins between 0<z<2.5. We find that the high-redshift (z>1) sources have an average q_24_ ratio which is better fit by local LIRG SEDs rather than local ULIRG SEDs, indicating that high-redshift ULIRGs differ in their IR/radio properties. So, ULIRGs at high-redshift have SEDs different from those found locally. Infrared-faint radio sources are examined, and while nine radio sources do not have an MIPS detection and are therefore radio-loud active galactic nuclei (AGNs), only one radio source has an extreme IRAC 3.6um to radio flux density ratio indicating it is a radio-loud AGN at z>1.
