The Las Campanas Infra-red Survey. V. Keck Spectroscopy of a large sample of Extremely Red Objects

(Abridged) We present deep Keck spectroscopy, using the DEIMOS and LRIS spectrographs, of a large and representative sample of 67 ``Extremely Red Objects'' (EROs) to H=20.5, with I-H>3.0, in three of the Las Campanas Infrared Survey fields. Spectroscopic redshifts are determined for 44 sources, of which only two are contaminating low mass stars. When allowance is made for incompleteness, the spectroscopic redshift distribution closely matches that predicted earlier on the basis of photometric data. Our spectra are of sufficient quality that we can address the important question of the nature and homogeneity of the z>0.8 ERO population. A dominant old stellar population is inferred for 75% of our spectroscopic sample; a higher fraction than that seen in smaller, less-complete samples with broader photometric selection criteria (e.g. R-K). However, only 28% have spectra with no evidence of recent star formation activity, such as would be expected for a strictly passively-evolving population. More than ~30% of our absorption line spectra are of the `E+A' type with prominent Balmer absorption consistent, on average, with mass growth of 5-15% in the past Gyr. We use our spectroscopic redshifts to improve earlier estimates of the spatial clustering of this population as well as to understand the significant field-to-field variation. Our spectroscopy enables us to pinpoint a filamentary structure at z=1.22 in the Chandra Deep Field South. Overall, our study suggests that the bulk of the ERO population is an established population of clustered massive galaxies undergoing intermittent activity consistent with continued growth over the redshift interval 0.8<z<1.6.Comment: 27 pages, including 14 figures and appendix of spectra (at low resolution). Full resolution paper can be found at http://www.ast.cam.ac.uk/~md . To appear in MNRA

Film Review: Narco Cultura – A Tale of Three Cities

This is a film review

Suicide Bombings in Operation Iraqi Freedom

Suicide bombing is the act of blowing oneself up in order to kill (destroy) or injure (damage) a target. The target may be military or civilian or both. Typically, the killing or physical destruction of the target is less important than the terror generated by undertaking the act. This ultimately makes suicide bombing a “disruptive firepower” capability (based on Bond-Relationship Targeting) utilized by opposing forces (OPFORs) which lack traditional destructive firepower

VBIEDs in the Mexican Criminal Insurgency

At least 130,000 people have been killed in the ongoing Mexican “crime war,” and many more have been kidnapped or simply gone missing. Yet despite the significance of these numbers, official reports and news accounts frequently underreport the toll of this war

Extreme Barbarism, a Death Cult, and Holy Warriors in Mexico: Societal Warfare South of the Border?

This short essay is about impression—gut feelings combined with a certain amount of analytical skill—about recent trends taking place in Mexico concerning the ongoing criminal insurgencies being waged by the various warring cartels, gangs, and mercenary organizations that have metastasized though out that nation (and in many other regions as well). The authors spent over eight hours sequestered together about a month ago on a five-hundred mile ‗there and back again road trip‘ to attend a training conference as instructors for the Kern County Chiefs of Police. Our talks centered on Mexican Drug Cartels, 3rd Generation Gangs, 3rd Phase Cartels, Criminal Insurgency Theory, and a host of related topics most folks just don‘t normally discuss in polite company. In the car, and at the conference, we were bombarded by Sullivan‘s never ending twitter and social networking news feeds—in Spanish and English—linked to the criminal violence in Mexico. If Dante had been our contemporary, we fear, he could just have easily taken a stroll through some of the cities and towns of Mexico using those news feeds and substituting the imagery for the circles of hell he described in his early 14th century work the Divine Comedy

Cartel Bombings in Mexico

Contemporary Mexican cartel use of car bombs began in mid-July 2010 and has since escalated. Given the proximity to the United States, some literally within miles of the border, the car bombings, with about 20 incidents identified over the last 2 1/2 years, should be of interest to local, state, and federal U.S. law enforcement, the U.S. Army, and other governmental institutions which are providing increasing support to Mexican federal agencies. An historical overview and analysis of cartel car bomb use in Mexico provides context, insights, and lessons learned stemming from the Medellin and Cali cartel car bombing campaigns. In order to generate insights into future cartel car bombings in Mexico, the identification of such potentials offers a glimpse into cartel “enemy intent,” a possible form of actionable strategic intelligence. For Mexico, steady and both slowly and quickly increasing car bomb use trajectories may exist. The prognosis for decreasing car bomb deployment appears unlikely. If cartel car bombs were to be deployed on U.S. soil or against U.S. personnel and facilities in Mexico, such as our consulates, we could expect that a pattern of indications and warnings (I&W) would be evident prior to such an attack(s). In that case, I&W would be drawn from precursor events such as grenade and improvised explosive device (IED) attacks (or attempted attacks) on our personnel and facilities and on evolving cartel car bomb deployment patterns in Mexico. The authors conclude with initial recommendations for U.S. Army and defense community support to the military and the federal, state, and local police agencies of the Mexican state, and the various U.S. federal, state, and local police agencies operating near the U.S.-Mexican border. The extent of support in intelligence, organization, training, and equipment is highlighted, as well as the extent that these forms of support should be implemented to counter cartel vehicle-borne IEDs and overall cartel threats

Criminal Insurgencies in Mexico: Web and Social Media Resources

The authors of this piece, individually, collectively, and in cooperation with other scholars and analysts, have written about the criminal insurgencies in Mexico and various themes related to them in Small Wars Journal and in many other publications for some years now. The Small Wars publications alone include State of Siege: Mexico\u27s Criminal Insurgency, Plazas for Profit: Mexico\u27s Criminal Insurgency, Cartel v. Cartel: Mexico\u27s Criminal Insurgency, The Spiritual Significance of ¿Plata O Plomo?, Explosive Escalation?: Reflections on the Car Bombing in Ciudad Juarez, and The U.S. Strategic Imperative Must Shift From Iraq/Afghanistan to Mexico/The Americas and the Stabilization of Europe. Certain truths have become evident from such writings and the raging conflicts that they describe and analyze

Third Generation Gang Studies: An Introduction

This paper reviews the literature and research related to third generation street gangs. Widely known as third generation gangs (3 GEN Gangs), these complex gangs operation with broad reach—often across borders—and have mercenary and at times political and potentially terrorist objectives. These are frequently identified as transnational gangs, known as Maras, and occupy the 3 GEN niche. The typology of the three generations of gang revolution, based on the interaction of three factors: politicization, internationalism, and sophistication found in the literature is also described. Finally, future research and security concerns are identified

Serendipitously Detected Galaxies in the Hubble Deep Field

We present a catalog of 74 galaxies detected serendipitously during a campaign of spectroscopic observations of the Hubble Deep Field North (HDF) and its environs. Among the identified objects are five candidate Ly-alpha emitters at z > 5, a galaxy cluster at z = 0.85, and a Chandra source with a heretofore undetermined redshift of z = 2.011. We report redshifts for 25 galaxies in the central HDF, 13 of which had no prior published spectroscopic redshift. Of the remaining 49 galaxies, 30 are located in the single-orbit HDF Flanking Fields. We discuss the redshift distribution of the serendipitous sample, which contains galaxies in the range 0.10 < z < 5.77 with a median redshift of z = 0.85, and we present strong evidence for redshift clustering. By comparing our spectroscopic redshifts to optical/IR photometric studies of the HDF, we find that photometric redshifts are in most cases capable of producing reasonable predictions of galaxy redshifts. Finally, we estimate the line-of-sight velocity dispersion and the corresponding mass and expected X-ray luminosity of the galaxy cluster, we present strong arguments for interpreting the Chandra source as an obscured AGN, and we discuss in detail the spectrum of one of the candidate z > 5 Ly-alpha emitters.Comment: 18 pages, 9 figures, accepted for publication in the Astronomical Journa